compile_kb: add new search functionalities (dict and shortest paths)
wdict: respect the relative order of the concepts associated to a headword.
test: Add more ppv tests
store POS field as a string instead as a char (allows to have POS field with more than 1 character)
csentence: add debug function
test: add ppv static test
wdict: new representation, storing the concepts grouped by POS.
Changes in csentence
wdict: add comments
wdict: fix bug when there are no valid concepts associated to a headword
wdict: don't use string pointers in dictionary map. It gains nothing.
Introduce --altdict option for including an alternate dictionary which overrides the main dict (or adds more entries).
wdict: add << operator to WDict_elems
csentence: add concepts to nopv words in context
csentence: any new CWord resets last nopv.
fix a bug in ppr (no w2w) with nopv cwords
Require boost 1.44 or higher to properly compile ukb