gtlua: implement first version of custom visitor
gtlua: implement first version of custom stream
add test cases for custom streams
add tests for custom visitor
improve error checking in gt_inlineseq tools
Merge pull request #357 from satta/lua_customstreams

Add Lua custom stream and visitor support
Merge pull request #358 from satta/inlineseq_errorcheck

improve error checking in gt_inlineseq tools