add gt_grep_escape_extended()
fix error reporting
escape seqids as patterns in -matchdesc
extend Lua Range bindings
Merge pull request #331 from satta/regex_escape

Implement escaping of seqids for use as regex patterns in -matchdesc
add io functions and functionpointer types module
add file io to intset
use io module
remove inline, would not apply
remove stray >
Change io from hard exit to using GtError
fix logic errors, cosmetics, assertions

lots of cosmetic changes
added assertions for set errors
fixed two cases of logical faults !had_err -> had_err
Merge pull request #332 from satta/lua_range

extend Lua Range bindings
make function easyer to use and fix comment
Merge pull request #315 from Garonenur/intset

file io