front: Rename gln64 option "disable depth test" to "enable depth hack".

This is a long-standing wording mistake that I made.  This is more
accurate.  The boolean meaning is inverted, thus the default value is
inverted.
front: Add wiki url to RomDetail class.
front: Add utility method to launch URI by string.
front: Add item in PlayMenuActivity to launch game wiki page.
front: Allow touchscreen/controller profiles to have no default.

In case the user wants the default touchscreen/controller to be
"disabled".  Emulation profiles cannot be disabled, and therefore
unsetting the default emulation profile will always revert the default
to what it was right after installation.
front: Move some touchscreen options to global settings.

The following are now specified globally:
 - haptic feedback
 - joystick refresh rate
 - button transparency
 - button scale
 - button style (skin)

Touchscreen profiles now specify only
 - button layout
 - button auto-holdability