Updated Simulation to support class-based models
Pass src_properties and dest_properties in projection specifiations rather than whole projection
Fixed for recent commits
Multiple small fixes suggested by Tobias
Updated lancet submodule reference
Merge pull request #577 from Tobias-Fischer/projection_properties

Pass src_properties and dest_properties in projection specifiations
ChannelGeneratorSheet now available from topo.sheet
Merge pull request #578 from jlstevens/master

Updated Simulation to support class-based models.
Eliminated redundancy in projection access
Improved Simulation call method and added docstring
Fixed bug in definition of opponents
Fixed bug in path specification for projections