This big patch cleans up the code per hlint indications. Many removals
of extra parentheses, replacements of concat . map with concabtMap,
extra dollar signs, eta reductions, etc. were performed.

The code still compiles and passes a couple of manual tests on sample
files. The individual changes are also small enough as to be visually
easy to confirm.

Currently hscan has a number of bugs:
  - doesn't add the common suffix (csf) to the instance's nodes
  - doesn't export the cpus for neither nodes nor instances
  - doesn't support single-node instances

This patch fixes these issues.

In a few places (e.g. tryRead or any printf call) it's a little bit hard
to add the correct type signatures, but in the it is possible to fix
these warnings (which can bite one in subtle cases).

This doc-patch adds copyright and license information to (hopefully) all
needed files.

This patch makes the Types module a base module, and Node/Instance ones
import it, from the previous (opposite) situation. This will allow in
the future to use newtypes for the index and name types.

This removes the return of ktn/kti from Loader.mergeData and associated
functions.

This patch removes all uses of ktn/kti from the past-loader stages.

Since we have Node/Instance.name, we can now simplify a few constructs.

This moves the remaining loading function to Loader (together with its
associated support functions).

This patch generalizes a little the CLI handling by not passing in a
special function for help and such, but instead requiring that the
options object supports some common functionality.

This new big patch does a couple of more cleanups in the loading of data
chapter:
  - introduce a Types module that holds most types (except the base
    Node/Instance/etc.) so that multiple other modules can use these
    (instead of only Cluster and its users)
  - bring IAlloc.hs in line with the recent changes of providing data
    types and not strings
  - removal of obsolete Utils.hs json-related functions

This big patch changes the loader model from “string data as common
format” to actual object structures as common format.

The text loading function move from Cluster.hs to a new Text.hs module,
some common functions are moved to a new Loader.hs module, and the
return values from both Rapi.hs and Text.hs are uniformized.

This patch changes Cluster.loadData to return a Result, instead of
directly the values; this will allow us to return meaningful error
values (e.g. when an instances lives on unknown node) rather than simply
abort. Currently the result is always an Ok, the actual signalling of
errors will come later.

Its callers are changed to accommodate for the new return type and to
display errors as needed.

In case we pass a fully-specified URL to hscan, currently it will use as
is and that means the directory in which we want to save the status
files changes from what we mean. This patch changes hscan to replace all
slashes in the cluster name with underscores when generating the output
filenames.

This big patch converts from our home-grown monad-like constructs
(the Either stuff) to a real, Either-like-but-another-name monad.

We introduce a “Result a” monad, and this allows dropping many of the
extra constructs. Hopefully the code is also more clear.

Many of the functions could now be written in a generic-monad style,
instead of Result specifically, but that will come in future patches.

IAlloc.hs also has some unrelated patches.

This patch drops compatiblity with Ganeti 1.2 and adds support for
offline nodes in the cluster. When reading from RAPI, the drained nodes
are considered offline so that we don't allocate on them too.

If an instance is down, it's memory is not reflected in the node used
memory, and thus the node free memory is higher than the actual value.
This patch deducts the memory for such instances from the node free
memory, allowing a correct calculation for such cases.

This patch modifies Rapi, the Cluster.loadData and hscan serialization to load
and save the instance run status. At instance level, we add both a boolean
field denoting the true/false run status, and a string field which holds the
original value (since we don't have a 1-to-1 mapping) for use in hscan
serialization.

The run status is not yet used.

This patch adds checking of cluster data in the binaries and display of
node's x_mem/i_mem in the node list.

This patch moves the common CLI functionality (as much as currently
possible) into a separate module. This means we only have one parseOpts
and that Utils.hs doesn't keep this kind of functions anymore.

This patch adds a new n_mem field to the node objects, and implements
read/save/show support for it. The field is not currently used (except
in the node list) but will be used for checking data consistency and
instance up/down status.

This fixes a mistake between Int/Integer. Should be more careful :)

This patch adds an hscan tool that loads data from clusters via RAPI and
writes it to files that can be later used offline.