add a newline
Remove docs and refactor style of TextView class.

* Make pointer style consistent, const char* name instead of const char *name.
* Lots of parameter renaming.
* in parameters don't get anything special, just font, or length instead of
  inFont, inLength.
* out parameters get a leading _ so *outWidth becomes *_width for example.
* We don't detail private function in the Haiku book and this class has a bunch
  so keep the documentation in the file but use regular comments instead.
* Normalize the parameter names between cpp file and header.
* Some minor whitespace fixes.

No functional change intended.
Add BTextView class docs