Fixed compilation on GCC.
Merge pull request #237 from theunknownxy/gccfix

Fixed compilation on GCC.
updated resource path
Precise OpenAL error checking which reports line number, and the setting to suppress AL error (response to #234)
Merge pull request #240 from noway421/readme_update

Updated readme
Merge remote-tracking branch 'origin/master'
use `asOFFSET` instead of `offsetof` because compilation fails on gcc-4.8
Merge branch 'master' into ngspades