Bugfixes for v1.4

* CLEANUP: Remove all traces of /data/app themeing
* FIX: Remove the placeholders that are also inside each folder in "new"
* FIX: Use full path in '$(ls)' during backup
* CLEANUP: Remove quotes from variables in 'if' statements, use '=='
instead of '-eq'
* FIX: Reintroduce theme file check for system apps (IDK why this was
missing in the first place)