Remove unused function
Fixed ID assignment
Renamed misleading variables
Removed unused function
Removed unused function
Switched private members to PIMPL

This removes the need to install the libjson headers, which were just an
implementation detail
Fix warning in third party library
Removed unused functions
Added default implementation of reclaimEvent

No models use this function. It should probably be removed.
Added default implementation of deallocateState

As with reclaimEvent, no models make use of this function, so it should
probably be removed.
Added default implementation of finalize

It doesn't need to do anything, why force every model to define it?
Added multiple jobs to speed up travis build
Added header to SOURCES variable

Headers need to be listed in SOURCES in order to be copied for VPATH
builds
Added multiple jobs to distcheck
Removed unused function getStateSize
Removed commented out code
Added default implementation of finalize
Split AC_CONFIG_FILES into multiple lines
Added default implementation of getTime functions
Moved member assignment into initialization list