Merge pull request #20 from guangbin79/xthread

add xthread/xhttp/xlongjmp
add api: xtime/xdebug/xfile
Merge pull request #17 from caiywHub/feature_1

add api: xtime/xdebug/xfile，缺少xtime的部分实现
fix xC.pro/xdebug/xfile
Merge pull request #22 from guangbin79/fix_api

fix xC.pro/xdebug/xfile
fix compile warnings
Merge pull request #23 from guangbin79/fix_api

fix compile warnings
add api xmemory/ximage/xtimer
Merge pull request #25 from mgya/wangxt

add api xmemory/ximage/xtimer
xfont / xgl / xopengl -- impl.
Merge pull request #14 from tangbo2013/develop

impl xopengl.h / xgl.h / xfont.h
add api: xrand/xtapi