Allow aggressive splitting.

Aggressive splitting splits camelCase, snake_case, terms with numb3rs in
them, hyphen-ated words, etc.  It might be good in all wikis but for now
it only works in English.

Bug: 54799

Change-Id: I6a84835ea5d6463f10e4fcd5bb228e1ffd252a28
Merge "Allow aggressive splitting."