Text Selection: smart word detection. DO NOT MERGE.

Selecting between words selects the spaces instead of the closest word, facilitating
paste insertion vs word replacement.

Pasting adds/removes space before and after if needed so that pasted text is not appended to
existing text.

Cut and copy not available when selection is empty.

Change-Id: I331413bdef341a4eceffe76fa2957f388d540b6e