fix compilation on mips

For mips64 and mips64el, they use -mabi=64 instead of -m64.
Thanks to Yunqiang Su for the patch (Debian #747431).
Merge pull request #303 from satta/mipsfix

fix compilation on mips
clean up public API and exported symbols in shared library
src_clean
add libtre to list of shared libs
fix GtRecMap API