Renaming implicit cleaning function
No need to have prop&clean implicit in one func. Use other funcs

Use already available functions to perform the same functionality
No need to prop&clean implicits here -- propagate() in Solver will do that

No need to duplicate functionality
Clean up after propagation in Simplifier
Never use assigns[], always use value()
Statistics should be collected by default
Adding end-of-file empty line
Removing useless comment

Comments get out of date. The code should explain itself through correct
variable&function names
Adding default cases in switch()

This is both for safety and to make the compiler stop complaining :)
Removing commented-out code

It only bit-rots for no reason. It's not needed, and most of it doesn't
even run any more.
Print restart stats less often
Removing code that is not used any more for watch consolidation
Doing more checks during re-creation of order_heap
Do gate-based ER if ER is turned on from the command line
Using a different heuristic for searching for ER in gatefinder
Memory can be saved in gate-finder
Using more const-ness
Using more const-ness
Fixing initialization order in constructor
Removing out-of-date comments