purge dead code

This is all unneeded remnants from taking the code from the Android guts.
Some of this stuff might later be re-added, but it can easily be taken from
the Android guts again.  Right now its just filling up this code base with
clutter.

fixes #1655 https://dev.guardianproject.info/issues/1655
refs #1658 https://dev.guardianproject.info/issues/1658
REBASE convert key type to char[] to allow zeroing