Lots of warnings: unused variable; may be used uninitialized in this function

[frankvg]

With GFX 1.1.5, in IDE 1.6.9, using Teensy 3.2, each compile shows a number of warnings. It's obvious none of these are all that important and the code functions fine. It is somewhat annoying to have all these errors when compiling and I'd prefer not to shut off warnings. These warnings include:

C:\Apps\Arduino\hardware\teensy\avr\libraries\Adafruit_GFX\Adafruit_GFX.cpp:566:14: warning: unused variable 'xa' [-Wunused-variable]

C:\Apps\Arduino\hardware\teensy\avr\libraries\Adafruit_GFX\Adafruit_GFX.cpp:392:27: warning: 'byte' may be used uninitialized in this function [-Wmaybe-uninitialized]

C:\Apps\Arduino\hardware\teensy\avr\libraries\Adafruit_GFX\Adafruit_GFX.cpp:410:27: warning: 'byte' may be used uninitialized in this function [-Wmaybe-uninitialized]

C:\Apps\Arduino\hardware\teensy\avr\libraries\Adafruit_GFX\Adafruit_GFX.cpp:427:27: warning: 'byte' may be used uninitialized in this function [-Wmaybe-uninitialized]

C:\Apps\Arduino\hardware\teensy\avr\libraries\Adafruit_GFX\Adafruit_GFX.cpp:443:27: warning: 'byte' may be used uninitialized in this function [-Wmaybe-uninitialized]

C:\Apps\Arduino\hardware\teensy\avr\libraries\Adafruit_GFX\Adafruit_GFX.cpp:462:27: warning: 'byte' may be used uninitialized in this function [-Wmaybe-uninitialized]

C:\Apps\Arduino\hardware\teensy\avr\libraries\Adafruit_GFX\Adafruit_GFX.cpp:600:9: warning: 'bits' may be used uninitialized in this function [-Wmaybe-uninitialized]

C:\Apps\Arduino\hardware\teensy\avr\libraries\Adafruit_GFX\Adafruit_GFX.cpp:604:47: warning: 'yo16' may be used uninitialized in this function [-Wmaybe-uninitialized]

C:\Apps\Arduino\hardware\teensy\avr\libraries\Adafruit_GFX\Adafruit_GFX.cpp:570:14: warning: 'xo16' may be used uninitialized in this function [-Wmaybe-uninitialized]