Add intent-filter for application/octet-stream and extension

Some applications might not know the specific mime types for patch/diff files, so we should also filter for the generic application/octet-stream type as long as the uri has ".diff" or ".patch"

Fixes #1

Test Plan:
- Attempted to open a .patch attachment from Mailbox - works now.
- Opened a .patch file from Gmail - still works.
- Launched an unrelated file:// intent with application/octet-stream - superdiff doesn't show up as expected