Move Drawer items back into DrawerActivity

Separating the items and the activity classes they call is not very
useful.
Embed K-9
Refactor showPassphraseDialog

Now any FragmentActivity can easily call it with its own  Handler,
no need to rewrite the same function over and over.
Make getDecryptionKeyId more robust

Now it won't bail on armored signed-only data.
get decryption key
Fix passphrase cache service

For symmetric keys always assume that they need a passphrase.
Make Gmail character fixes actually work
snapshot