Reorganize the new code.

I wound up with multiple modules in src/modules so I'm splitting them up
so the code is easier to understand.

src/collection    - This is the collection backend that runs in the
                    registry service.  Its job is to find calendars
                    and address books and other such resources on the
                    Exchange server and add ESources to proxy them.

src/configuration - This is all the configuration UI which currently
                    runs only in Evolution.  Includes extensions for
                    mail accounts, calendars and address books.
Don't hard-code calendar and task list colors.

We allow these to be changed through Evolution.

We do still need logic to pick an initial random color so new calendars
are not all the same color, but that should live in ESourceSelectable in
libedataserver.
ebews_start_gal_sync(): Avoid crash when EwsOALDetails list is NULL.
Drop gconf-2.0 dependency.

There's still some dead code in the repo with GConfClient references.
I'll remove those shortly.
Bump minimum gtk+-3.0 requirement to 3.0.

Also bump the minimum glib-2.0 requirement to 2.28 since that's the
version GTK+ 3.0 required.
Updated French translation
Do not call g_object_notify() when property didn't change
Adapt to CamelDataCache API change.

camel_data_cache_get_filename() dropped its unused GError parameter.
Bug 678321 - Bug in usage of signed/unsigned crashes downloading of GAL
Updated Latvian translation
Whitespace cleanup.
Add untracked m4 files to MAINTAINERCLEANFILES.
NEWS update for 3.5.3 release.
Post-release version bump.
Bug #679305 - EX addresses not decoded in folder summary
Bug #679303 - Doesn't detect when password has changed
Bug #679305 - EX addresses not decoded in folder summary
Bug #663383 - Doesn't allow to quit
Fix crasher in oal_response_cb().

I introduced this in commit c85384779272821fcdf38383c8bc63891c88a04e.

Accidentally changed "if (!data->oal_id)" to "if (data->oal_id != NULL)"
when if should have been "if (data->oal_id == NULL)".

Testing pointers with an negation operator (!p) is less readable than
comparing to NULL explicitly (p == NULL).
Remove redundant method implementations.

By default, CamelStoreClass uses g_str_hash for its hash_folder_name
method, and g_str_equal for its equal_folder_name.  So we don't need
to override those methods to do exactly the same thing.