#2 Added support for filtering with multidimensional descriptor values
#2 Added documentation about multidimensional filtering
Modified parser so it accepts [] characters in filters
Fixed error in lexer.l
Updated parsertypes.h t work with new multidimensional filtering syntax
#2 Updated filtering docs
#2 Add a little bit more comments to parsertypes.h
#2 Updated filtering docummentation.
#2 Updated unitests for test_parser to test multidimensional filtering
Fixed bug in lexer.l that made gaia crash when filtering features with underscore (_) character in its name.
Merge remote-tracking branch 'origin/feature-multidimensional-descriptor-filtering'