Support for -pt_renumber(true | false) attribute

This attribute instructs parse_trans to renumber the abstract forms, incrementing
the line number for each form. Combined with -pt_log_forms(true), it can be of
use when tracking down compiler errors that result from code produced in the
parse transform.
exprecs now also generates functional lenses
slightly better error messages for codegen:gen_module/3
added codegen:gen_function_alt/3
codegen:gen_function_alt/3
Fix wrong type spec genration inside exprecs.
Merge pull request #8 from ddosia/dch-fix-exprec-spec

Fix #7 wrong type spec genration inside exprecs.
use installed rebar, if exists
empty records broke exprecs in #lens-
merge esl and uwiger repos