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 patch changes the format of the input node and instance lists. It
removes the list of primary and secondary instances from the nodes, and
adds the primary and secondary nodes to the instance list.

This is done so that we can have the same input data from commands as
from the RAPI.

This is the initial import of release 0.0.3.