cm: Minor config reorganization

 * Move extra tools to common.mk. These are needed for CMFM, and should
   be included for all.
 * Move LiveWallpapersPicker, SoundRecorder and Screencast
   to common.mk. These apps are extremely small, and only takes up
   less than 1 MB combined.
 * Move sound property overrides to common.mk. There's no need
   to have them spread across several files.
 * Include CM audio files from common.mk

RM-290

Change-Id: If308506cd9cd0a75014de988c242d700db5d16f3