Based on a patch by Tomasz Malesinski
* Merge Codec buffer and Malloc buffer into one large buffer.
* The new merged buffer is now 1MB on targets with lots of memory.
* Renamed codec_get_memory to codec_get_buffer and made it behave more.
like plugin_get_buffer.
* Bumped Codec api and min api versions.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@18834 a1c6a512-1295-4272-9138-f99709370657