Moving towards replacing const_monomial entirely with the types on Monoid.
Simplified PolyHashTable and gave BjarkeGeobucket2 a new hash table based on MonmialMap that is significantly faster than the old one.
Moved a line in BjarkeGeobucket2 that is a boost to performance.
Moved PolyHashTable closer to BjarkeGeobucket2's hash table and removed several superfluous reducers.
Improved the implementation of ReducerHashPack so that it is a bit faster and so that it does not move monomials out of hash table nodes. The latter was a barrier to making changes in PolyHashTable.
Replaced the interface and implementation of PolyHashTable with the better hash table from BjarkeGeobucket2. That made BjarkeGeobucket2 superfluous, so it was removed.
Moved some of the code of PolyHashTable into its implementation file.
Clean up of Reducer header file and remove statistics functionality from there. If we need that functionality in future, it should be implemented using the logging facility, not as a part of the main-line code.
Made registering a reducer type depend on a decentralized method instead of having a big function in Reducer.cpp do it, leading to long compile times when that file needs to be recompiled. The new method is now implemented and being used for ReducerPack. The remaining reducers are using the new method, but it is still being done from Reducer.cpp. Next up: migrate all new reducers to this new way of doing it.
Moved the implementation and even declaration of all reducers out of their header files. Registration of all the reduers now happens in a decentralized fashion in each reducer's .cpp file. Reducer.cpp no longer takes so long to compile.
Light cleanup of the reducer implementatio files.
Converted all non-F4 reducers to new MonoMonoid monomials and documented them.
Merge branch 'master' of https://github.com/broune/mathicgb into broune

Conflicts:
	src/mathicgb/F4Reducer.hpp
	src/test/gb-test.cpp