add file: ximage.h / xlongjmp.h / xmemory.h / xtapi.h / xtime.h / xtimer.h / xthread.h
Merge pull request #7 from guangbin79/system-api

add file: xsetjmp.h / xtapi.h / xtime.h
add xdebug.h xfile.h xfont.h xgl.h xopengl.h

Add space between struct name and "{".

xopengl.h modify func name err.
Merge pull request #8 from tangbo2013/develop

add xdebug.h xfile.h xfont.h xgl.h xopengl.h
update README.md
Merge pull request #9 from guangbin79/readme

update README.md  merge.
add xhttp.h and xrand.h.
Merge pull request #10 from tangbo2013/develop

add file: xhttp.h and xrand.h.
fix file: xhttp.h
Merge pull request #11 from guangbin79/http_fix

fix file: xhttp.h merge to master.
api impl demo
Merge pull request #12 from guangbin79/feature_http

api impl demo， merge.
fix file: xinteger.h
Merge pull request #13 from guangbin79/fix_integer

fix file: xinteger.h, merge.
api impl demo - 1
Merge pull request #15 from guangbin79/feature_http

api impl demo - 1