calculator: Calculate action now valid for other mathematical operators

Signed-off-by: Karol Będkowski <karol.bedkowski@gmail.com>
calculator: add missing operators (&|~); update description and manual
calculator: separate action for expression with and w/o =

Expression that not start with = should have lower rank. This prevent
setting calculate action for i.e. url.
calculator: change localized decimal point symbol to dot
gtg: workaround for broken GetTasks method in GTG DBUS API

Try to read tasks via GetTasksFiltered when no results via GetTasks
plugin_support: fix problems with save passwords in keyring lp1056686

Keyring no longer support username as unicode

Fix: LP1056686
trash +EmptyTrash action

Author: J <j49137 gmail com>
websearch: find all search plugin from firefox/iceweasel

+ load search plugins from more standard dirs

Closes: lp#799332
Added check for no alternatives when getting settings.

Addresses Launchpad bug 841867.

Author: David Schneider <dnschneid gmail com>
Closes: lp841867
session_gnome: support Gnome3 for logoff/shutdown actions

Closes: lp#788713
Author: Joseph Lansdowne
gui/preferences: update plugin info on activate/deactivate plugin by keyb.

Author: Joseph Lansdowne
Closes: lp#785963
rhythmbox: use dbus to control rhythmbox and load library

Not all functions needed by Kupfer are available via dbus.
Still some parts via cli.
plugin top: fix for locales not using dot as decimal point.
preferences: prevent Kupfer crashing on broken .desktop files

Closes: lp#1089347
preferences: catch exceptions when loading .Desktop files
firefox: check is bookmarks file exists before loading it