Display sync errors using snackbar and not as a TL footer

b/16463253

The FAB compose button overlaps the action button found in the TL footer
when network errors occur during sync. To avoid this overlap, the snackbar
is used to display these errors and they no longer appear as a TL footer.

In order to signal the sync error to AAC for display in the snackbar, the
Folder.lastSyncResult needed to be encoded in the manner that AAC reads.
This was not happening for POP/IMAP/Exchange accounts, so a large portion
of this change is encoding that value properly every place it is written.

To ensure the value is read/written properly everywhere, common methods were
introduced in UIProvider that do this work. UIProviderTest was also added
to ensure the read/write methods agree with each other.

Finally, the display of the "Load More" TL footer was updated to match the
latest spec.

Change-Id: Ib8692a2b9e164d25f982a2d7a54b07d2d3950358
1 file changed