Add keywords for existing functions

Since the recently added MicroViewFlashingHeart example sketch uses them, I assume that the uView.setPageAddress(), uView.setColumnAddress(), and uView.data() functions are officially sanctioned for general use. These changes just add *setPageAddress*, *setColumnAddress* and *data* as keywords.

Also, the *getScreenBuffer* keyword was moved to a more appropriate location in the file and a duplicate of the *invert* keyword was removed .