Small updates to the documentation and make a new small release.

During a replace-primary instance move, on the real cluster the instance
is temporarily started on the secondary, and as such we must check that
the secondary node can hold it for this duration. Currently the code
does not, and depending on cluster scoring it will put instances on such
'bad' secondaries (usually without enough memory).

This patch fixes this by adding/removing the instance as a primary on
the secondary node; and then using the result node as the new secondary.
(Since we're in a monad, we could have just tried the allocation and
dropped the result, but this is more clear).

This also fixes other required node numbers.

Currently tryAlloc/tryReloc do not return the new instance, as this is
not needed for IAllocator alloc/reloc requests. However, for computing
the space, the new instance is useful, so we modify these functions to
return this information too.

The patch also improves hspace to have (with default parameters) a
parseable output.

This is a tool that checks how many instances (of same size, specified
by command line arguments) can be added to a cluster while remaining N+1
compliant.

And an alignment issue.

This patch makes sure that all references to the name of the software is
ganeti-htools, not simply htools.

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

This patch moves the test declaration into QC.hs, so that test.hs has to
be modified only when we add a new test category.

These are generic enough to be used from multiple places, they belong
better in Cluster.hs than in the hail source.

These two will be more generic than now, and belong somewhere else -
Loader.hs is a generic module for data loading, thus we move them there.

Also replace a type with its synonim.

This patch does only doc build changes, doc changes and function move
around (for more logical documentation). It should have no impact at all
on the code.

Since ghc won't trigger recompilation due to the -fhpc flag, it's not
useful to rm && make test, as this will only relink the binary.
Therefore we simplify this rule.

This is more of an exercise in QuickCheck than strong testing.

This completes the removal started earlier byt removeing the need to
pass the number of nodes to Node.buildPeers, which is now unused.

This patch adds a QuickCheck-based test infrastructure and initial tests
based on it. The PeerMap module has a 100% coverage ☺️

Side-note: one has to read the source of QuickCheck to see how to use it
(especially the Batch submodule), the docs are not enough…

This patch removes some unused functions and does some cleanup of the
remaining ones.

We remove some unused arguments (added way back for compatibility with
Arrays, which we didn't use in the end). This makes the code clearer
(and doesn't need the Ndx type to be an instance of Num).

Currently we (wrongly) use lookupNode to lookup instances, just because
the name assoc list has the same type. This patch adds a separate
function for it.

This is a first step towards full datatype renaming. That requires more
changes, so at first we only want to document clearly what is a node
index, what is an instance index, and what is a plain Int.

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 splits the current “clean” rule into proper clean (cleaning of
build artifacts) and maintainer-clean (cleaning of distributed files).
This should make it better for Debian packaging.

The IAllocator source was copied from Rapi before the offline node fixes
were made. This changes such that offline nodes are accepted correctly.

Also replace tabs in an older entry with spaces.

Currently iallocator is broken when reading single-node instances (and
with an ugly error message). This patch fixes this case, by marking them
with secondary node “noSecondary” like the rest of the code.

This patch fixes the relocate-to-primary-node problem, and doesn't mark
the excluded nodes as offline anymore (we don't use them anyway, so
let's not use a different/fake cluster state).

Slash is a reserved char. Slash is a reserved char. Slash is a…

This patch implements filtering out of the offline/drained nodes and
fixes a bug in IAllocator.hs parsing (similar to an older bug in Rapi.hs
from where the code was copied).