Fixed duplicated variable nodes
Remove some old cruft.
Partial conversion to class scored_combo_tree

The nested pairs of pairs of pairs has gotten very challenging to
debug (never mind read and understand, for newcomers)  Start fixing
this.
Ongoing refactoring of the scored tree system.

The code still doesn't compile. But we're getting closer...
Added a dump file.
Added test function for test a crash in Pattern Matcher.
Merge pull request #788 from shujingke/PM

Some test about pattern matcher in pattern miner.
Ongoing refactoring of the scored tree system.

All code compiles, one unit test fails.
Fix combo tree hashing function
Merge pull request #790 from linas/clust

MOSES: rework the scoring infrastructure.
fix compiler warning
more strength reduction in the MOSES scoring code.

All test cases pass at thsi point.
More MOSES scoring strength reduction.
Remove some dead code from combo
Merge pull request #791 from linas/sco

MOSES scoring strength reduction
MOSES: get rid of penalized_behavioral_score

This object was not general enough to deal with the various different
scoring adjustments that need to be made.
moses scoring: get rid of the overloaded accessors
Rename the bscore_based_cscore class
Improved documentation for scroing functions
correct implementation of complexity computation.