A new algorithm for jalaali date calculations

Started using https://github.com/jalaali/jalaali-python for jalaali date conversions since it is more accurate.

Prepare for flathub release

v5.0.0.rc1

improve appdata

Version 5.0.0.rc0

A complete re-write of the application.

Version 4.5.0

Adds support for Afghan month names.
Fixes #23

Version 4.4.1

Added support for newer gnome-shell versions

Version 4.4.0

Fixed issues #16, #17, and #18.
Added Travis-CI integration.
Updated translations.
Header-bar is enabled.
Fixed packaging bugs and added new packaging.

Version 4.3.4

Uses a hidden icon for appindicator.

Version 4.3.3

Adds support for Lubuntu and Gnome 3.16.
Fixes some issues.
Fixes some packaging bugs.

Version 4.3.2

Fixes both debian and archlinux packaing issues.
Adds a new Status Icon (system tray icon) as a plugin.
Small UI changes.

Version 4.2.6

adds compatibility for ubuntu 14.04
adds compatibility code for Gtk 3.10
adds better debian packaging
does not disable plugins when app crashes
removed header bar from preferences dialog
fixed a bug when external khayyam was being imported
dialog window is used instead of popovers in gtk 3.10
fixes a bug when toolbar was not showing the today button