Modify KeychainIntentService to support I/O with URIs, allow input and output to/from different types (eg. encrypt file and return byte array)
Use Document API on KitKat for file encrypt/decrypt
Delete using Document API (unsafe)
Merge branch 'master' into improve-file
Merge branch 'master' of https://github.com/open-keychain/open-keychain into improve-file
Merge pull request #664 from mar-v-in/improve-file

Add Document/Storage API support