Don't assert() if Imap.Folder created w/ mismatched name: Bug #739316

The assertion was a sanity check that's outlived its original purpose.
When it triggers now, it means an internationalization/encoding issue,
usually with non-Gmail servers that implement XLIST.  Rather than
assert and make Geary unusuable for a subset of our non-English
speaking users, log a message and continue.
Return to IDLE properly when connection lulls

Commit 96aaf3 fixed a bug with regard to IDLE status responses being
improperly reported to ClientSession.  As it turned out, that fix
introduced a bug by not properly decrementing outstanding_cmds, which
left the ClientConnection in a state where it would never enter IDLE
thereafter.

The problem is a change I pondered at the time but didn't commit due
to that fix being so close to release time: not reporting the original
IDLE command to ClientSession either.  That in itself is harmless, but
not doing that also avoids incrementing outstanding_cmds for that
command, meaning when the IDLE completes that value returns to zero
and the ClientConnection is in an appropriate state to return to IDLE
when ready.
Geary window does not open due to race condition: Bug #737811

Although prior fix for bug #737811 solved problem for some users,
apparently Geary still had an issue when upgrading a database with
new GLib Mutex implementation, which uses Linux's futexes whenever
available.  This solution gives the notifying thread a chance to
signal the waiter that its work is completed.
Vala 0.28 now warns about unused/unknown attributes: Bug #741077
Update POODLE SSLv3 fallback string: Bug #741132

As recommended by bug #738633 comment #21.
Update to 0.8.3