Decrypt Tested it. 

Test Cases:
1) For files, Took a file encrypted it, stored it. Fetched it in decrypt file fragment (Error: InputBufferStream is fixed) Decrypted it and I have got the file in OpenPgp-Keychain folder (default folder).

2) Messages are automatically decrypted.

Error:InputBufferStream is caused because  ``` instream.close() ``` is called in ``` finally{} ```
I could not complete Layout issue with Message editbox. I tried now and i failed.
If that is the functionality of decrypt activity. I guess its fine.

I have not tested handleIntents() and startActivityResult() based calls. Please help me that.

#401