[rbp/omxplayer] Fix build error in types for max

It seems there is a compile error when STDINT_H_AVAILABLE is not defined.
See: http://raspbmc.apt-get.eu/downloads/bin/xbmc/nightlies/xbmc-rbp-20130710.log
Merge pull request #2968 from popcornmix/fix_max_types

[rbp/omxplayer] Fix build error in types for max
fixed, add float to float convert with a copy so we do not have to check convertFn for null all over the place
changed, include AE_FMT_S16NE as avaliable format on audiotrack sink
changed, audiotrack, add volume/drain locks, default volume to 1.0, remove AE_FMT_S16NE handling
[rbp] Added a boolean condition to identify the Raspberry Pi platform (System.Platform.RPi)