Segmented control mode & fixed issues.

I've added more color customization options and a possibility to specify a selected button, making it very similar to a segmented control.

I've also fixed some drag and touch cancel issues.

Consider merging or just cherrypick the fixes:
https://github.com/rokgregoric/MenuPopOverView/commit/919d82f6e857873f5ebcefdc2b864795b1c9eedb