Remove instance data from OakTextView.h
Harmonize a few properties

This is just implementation detail.
Disable font smoothing for dark themes

If you wish to always have font smoothing enabled you can run:

    defaults write com.macromates.TextMate.preview fontSmoothing 1

Setting the value to 0 causes it to always be disabled and deleting the key (or setting it to 2) has it disabled only for dark themes.