Use Minikin grapheme cluster breaking

This patch uses the Minikin implementation of grapheme cluster breaking,
which improves the behavior of left and right arrow keys for moving the
cursor. Among other things, it fixes the behavior of jumping over the
"fi" ligature in Roboto.

Part of a fix for b/15653110 Improve behavior of arrow keys in EditText

Change-Id: I80ca54c973d85c49f23b81d51a0fe07a7a853d81