CMFM: CYAN-200 - Archiving and Extracting .ZIP files in CM File Manager

Added support for zip and unrar commands. Zip, unzip, unlzma, unxz, uncompress and
unrar are now optional. Compress or uncompress of these types are only available
if its commands are present in filesystem

NOTE: This change requires that zip and unrar commands are present in the
filesystem at /system/xbin, which actually don't.

Patchset 2: Rebased

Change-Id: I30667c802bc5b678015b28bb3170377ceb37a1b8
JIRA: https://jira.cyanogenmod.org/browse/CYAN-200
Bugfix: CYAN-200
Signed-off-by: Jorge Ruesga <jorge@ruesga.com>