Spell checking in TextViews

New UX interactions (the Paste action is no longer displayed after a delay)
suggestionEnabled flag replaced by existing input type flag.
removeSpans fixed in SpannableStringBuilder to always send notifications
SuggestionSpan handled by TextView instead of SpannableStringBuilder

New span update algorithm to correctly handle edition around word boundaries.

Change-Id: I52c01172f19e595fa512e285a565a3fd97c3c50e