Fix the examples in the documentation of letrec
Fix _c usage in the documentation
Simplify the implementation of binding a lambda abstraction in meta_hs
Merge remote-tracking branch 'upstream/master'
Fixing reg_exp and seq elements to iterate through their sequences with foldlp and foldl.
Making the bracket expression counter local. The bracket expression back-referencing need to be fixed.
Detailed sub-match comparison added to search.hpp
Interface for xlxpressive: xlxpressive.hpp