fmbtandroid/fmbttizen/fmbtx11: default opacityLimit changed (backward compabilty break)

The default opacityLimit is changed to 0.0, that is, possible alpha
channel of verified bitmaps is ignored. This makes the API consistent
(by default, always require perfect match for maximal
reliability). *Bitmap methods that currently use alpha channel for
ignoring comparison of some areas of must add explicit
opacityLimit=.95 optional argument.