Adds doxygen string to WeightPatternMonitor
Updates doxygen string in SpikingGroup
Adds new functionality to WeightPatternMonitor

This allows to limit the number of patterns used for readout which
is set to three by default. This was necessary because the readout
can otherwise quickly become a major performance bottleneck.
Fixes problem in WeightPatternMonitor

The problem arouse when different quantities of pre and post patterns
were loaded.
Adapts filenames in constructor to be of type string
Merge branch 'master' into devel
Merge branch 'master' into devel
Adds setter for refractory period to TIFGroup
Tentative changes to interpolation procedure
Adds setter for state vectors in NeuronGroup

This allows to set single elements (or all) elements of a StateVector
to be set by referencing it by name. This function could in principle
also move to SpikingGroup.
Bugfix in VoltageMonitor
Change to RateChecker

Now uses all spikes from all nodes to compute the current firing rate
for more consistent output.
Fixes bug in set_state function in SpikingGroup

This new function was creating problems on ranks with zero
elements in a node.
Changes scope of variable in SparseConnection
Fixes problem in StateMonitor

Fixes a problem which arose on ranks with zero neurons in a group.
Fixes a bug in localrank function in SpikingGroup

The bug caused problems with the new load_from_complete file
function when there were carry neurons in a ROUNDROBIN situation
or presumably also in a situation with RANKLOCK.
Decreases MINDISTRIBUTEDSIZE to 16
Fixes two occasions of mismatched use of use of delete
Minor changes to SparseConnection

Removes the prune function to discourage its use. Also it should
not be necessary to use it any more with the reimplementation of
load_complete_matrix.

Fixes two occurrences of mismatched new[] / deletes.
Removes prune functions in sim_brunel2k_pl