User docs: Fix styling+indents in calendar-*.page

Fix indents and add <app> tags around Evolution
in all calendar-*.pages.
Updated Brazilian Portuguese translation
Updated Galician translations
Updated Spanish translation
Tajik translation updated
Bug #720542 - Crash on calendar view's tooltip timeout
Fix indents, <app> tags for backup-restore.page

Indent backup-restore.page
Enclose Evolution within <app> tags wherever applicable.
Fix indents, <app> tags in remaining c*.page

Make indentation more consistent.
Enclose Evolution within <app> tags.
Updated Greek translation
Updated Spanish translation
Bug #724023 - Run EMailFormatter in the main/UI thread

Any GtkWidget creation or manipulation should be done exclusively
from the main/UI thread, thus make sure it is done that way.
Of course, evolution can freeze for a little time (depends on the message
size), until its formatting is done. It's unnoticeable with usual messages.
Bug #722041 - NNTP Messages are silently dropped from Outbox
Bug #655806 - Folder deletion is very slow
e_table_sort_info_duplicate: Missing ref of a 'column_spec' member

Both 'groupings' and 'sortings' arrays unref the 'column_spec' on removal,
but the 'duplicate' function didn't ref them, which caused use-after-free
at the end of the application.
Fix a runtime warning on startup.

Calling g_source_remove() on a saved source ID but not resetting the
source ID to zero.
EMailConfigAssistant: Hack the "Go Back" button after autoconfig.

After account autoconfiguration, you can click the "Go Back" button to
revise the account details.  That's been in place for some time now, but
it's not obvious from the button label.  "Go Back" implies going back to
the Identity page.

Temporarily rename the "Go Back" button on the Summary page to something
more accurate after a successful autoconfiguration, then reset it to its
original "Go Back" label.

Unfortunately the GtkAssistant API does not make this easy.  I had to
resort to crawling the assistant's internal child widgets and comparing
button labels to locate the right button.  So this hack may not be very
future-proof.
Updated Ukrainian translation
Updated Assamese translation
Updated Brazilian Portuguese translation
Stop using deprecated gtk-stock items