Added a multi-select touch listener.

Work in progress
Improved touch listener on the Calendar.

Selection is now done by drawing a rectangle
Added enable/disable selection methods.

Also fixed some bugs in selection
Added action bar toggle for selection mode
Selecting intervals instead of a box
Fixed incorrect row count in CalendarGridView
Improved calendar selection mode.

Now there is no need to toggle this mode. After a long press (500ms) it
toggles and scrolling is disabled. When the selection is done (ACTION_UP
or ACTION_CANCEL), selection mode is disabled and scrolling is
re-enabled.
Using GestureDetector insted of Runnable.

This makes it more standard, as long-press times are consistent
throughout this app and the Android OS.
Enabling/disabling side menu touch
Merge branch 'dev' into cal-selection