Refactoring term set for cut-introduction. FlatTermSet becomes TermSet and is implemented in the same file as TermsExtraction. A TermSet object is now the return value for TermsExtraction. The code is refactored accordingly and some variables were renamed for consistency purposes.

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@2217 85d21ef8-add0-11de-ae77-5bfb9c5a3f34
Removing uses of FlatTermSet.

git-svn-id: http://gapt.googlecode.com/svn/trunk/source@2218 85d21ef8-add0-11de-ae77-5bfb9c5a3f34