Add HDR option to GUI
Exposure is adjustable (`r_exposureValue`)
See http://en.wikipedia.org/wiki/Exposure_value
Perfect map self-shadowing
Removed direct light “Ultra” settings
Lens effect added to “High” post-effect settings
Smoother lens flare occlusion
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'