* renamed _FindXXXWordBoundary() methods to _Previous/_NextWordBoundary()
since the respective per-char methods are named this way
* started to work on improving the behaviour of page-up/page-down
git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@30012 a95241bf-73f2-0310-859d-f6bbb57e9c96