Address the 'ART' Issue

Rather than outright remove this completely, address primary concerns:

* Add a more verbose warning message on alert dialog
* Explicitly state experimental form
* Explicitly state not supported (no bug reports)
* Explicitly state issues (crashes, bootloop, etc)

Additionally, move option to 'Apps' header (bottom), as this is it's
primary impact.

See prior discussion: http://review.cyanogenmod.org/#/c/55609/

PS2: Linkify

Change-Id: Icf103b5576c8e93f8a30ccd348476bf207401355
Only show ART information if switching from dalvik to ART

We do not want to confuse users with a big information dialog, if
they change from ART to dalvik as dalvik is still the official
solution, supported and considered safe.

Change-Id: I0ce4846e0bb751e87e5c410e668d4bc521380141