clock: fix crash

https://bugzilla.gnome.org/show_bug.cgi?id=737575
clock: rename CLOCK_LOCATION_TYPE to CLOCK_TYPE_LOCATION
clock: add ClockTime
clock: update clock icons

Remove some unused icons and rename existing.
clock: rewrite ClockFace
clock: remove rsvg dependency
clock: move weather_info_setup_tooltip function
clock: rewrite ClockLocationTile
clock: detect timezone change

Unused at this moment, but will be used to update current location
when timezone changes.
clock: update weather tooltip setup function
clock: use g_define_type_with_private for ClockLocation
clock: move clock-format to ClockLocation
clock: reformat ClockLocationTile
clock: update clock_location_setup_weather_tooltip
clock: reformat clock-location.h
clock: update clock_location_new
clock: add ClockPreferences [untested code]
clock: rename clock.h to clock-common.h