NetworkModeTile: option to choose whether to use LTE or not
Even if device supports LTE we should allow to exclude LTE mode from
tile since it  depends if LTE network is available or not in the given
location (e.g. country).
This also replaces the hacky, partially working LTE detection mechanism
(not needed anymore).

Conflicts:
	src/com/ceco/gm2/gravitybox/GravityBoxSettings.java