USSDFilter_XposedModule

USSD Filter using the Xposed Framework.
Currently only 1 filter is supported using the file /sdcard(or equivalent)/USSDFilterString.conf
Substring matching implemented with Toast notification.
UI is not done yet

TODO

1. Preference activity
   1.1 Add button to add a filter
   1.2 Long press to show remove option
   1.3 Press to edit
   
2. Filter types :
   2.0 Priorty - number from 1. default = lowest
   2.1 Substring
   2.2 RegEx
   
3. Filter output:
   3.1 No ouput - completely suppress message
   3.2 Toast the message
   3.3 Show as notification
   
4. Donate (consumables for $1, $2 & $5)
   
5. About
   
6. Database to store settings and log
   
7. Log USSD messages
   7.1 Configurable log limit