Merge pull request #50 from gsdlab/develop

Release 0.3.6.1
remove LBNF
rename clafer-orig.cf to clafer.cf

grammar rewriting will no longer be needed
move grammar to src
reorganize Makefiles, remove redundant cleaning
removed productions for Pos and Span

They are not generated by bnfc
added alex and happy processing
removed Mapper, changed calls to `range` to `getPos`
removed PosPos and PosSpan
removed handing of Pos* types from Tracing
removed Pos* types from ClaferT
removed Pos* types from Desugarer
removed Pos* types from ClaferT
removed PosPos and PosSpan
Removed Pos* types from Html generator
Removed Pos* from Graph generator
Removed Pos* types from Clafer
removed module position mapping
Removed Pos* from Positive
do not clean Front anymore