Port WimaxHelper and (the toggle) WimaxButton from CM7.

Both WimaxHelper and WimaxButton are updated to support Samsung's
(crespo4g, epicmtd) Wimax4GManager proprietary class, whose API has been
somewhat-significantly changed in ICS.  Support for HTC's (supersonic,
speedy) WimaxController is retained in WimaxHelper, although untested.

Note that WimaxManagerConstants was previously misdocumented, confabulating
the lookup key EXTRA_4G_STATE ("4g_state") with EXTRA_WIMAX_STATUS
("wimax_status"), which no longer exists.  This is also fixed.

Change-Id: If6fc4a0a290ad9689a40ee06f9f6a2f3092cfaf9