Merge pull request #659 from OV2/master

(D3D) use new instead of calloc so that constructors are run
Move some enums outside of header file for backend
(Menu) Add input_axis_threshold option to menu
Cleanup menu_common.h
(Apple) Move Apple input files around - rename files
(Apple) Build fixes
(Apple) Bump up CFBundleVersion numbers
Lower OSX solution to 10.5 compatibility
clamp axis_threshold to avoid potential floating point issues.
Add core_info/rom_history extensions from Apple ports to mainline
(Apple) Build fix
(Apple iOS) Style nits
(MSVC) core_info.c - Fix signed/unsigned mismatch warning
(PPC OSX) Delete .build dir
(MSVC) Fix unreferenced variable warning
Avoid reading back random RGUI frames in async recording.
Add audio_enable option to FFemu.
(Menu) Add DSP filter options
(Audio DSP) Add audio DSP filters to audio/filters directory -
C convresions of original RetroArch-Audio-DSP-Plugins
Update audio/filters/link.T