PGP messages background decryption

Don't synchronize on non-final field

Handle some orientation changes manually

fixes the menu not being shown after rotation in edit account details

Currently most activities get destroyed/recreated when rotating the
device. This commit prevents this from happening where it is not
necessary.

The most obvious improvements are:

 * The options menu in the EditAccountActivity does not disappear when
   rotating the device.

 * CSI inactive/active states are no longer sent on every rotate.

move chat state reset from background switch to foreground switch to account for chat states sent in the mean time

cleaned up TrustKeysActivity to automatically close if there is nothing to do