Changed init routine , added configurable strobe delays

[adrianh-za]

I was having issues rendering readable text on my RPi3 Model B. After much trial and error, it would seem changes to the initialization routine, strobe delays and slight delays on "command" functions resolved the garbled text.

The initialization routine for the LCD display requires specific minimum delays between each init call. See NewLcd() for those changes and link to the datasheet.

Added two functions to set and get the strobe delays that get sent to the LCD display in writeDataWithStrobe() so that it can be configurable from the calling code.