Merge branch 'master' of https://github.com/olikraus/u8g2

cppsrc/U8x8lib.cpp

@@ -44,6 +44,9 @@
 #include <SPI.h>
 #endif 
 #ifdef U8X8_HAVE_HW_I2C
+#ifdef U8X8_HAVE_HW_I2C_TEENSY3
+#include <i2c_t3.h>
+#else
 #include <Wire.h>
 #endif
 #endif

cppsrc/U8x8lib.h

@@ -54,6 +54,11 @@
 */
 //#define U8X8_USE_ARDUINO_AVR_SW_I2C_OPTIMIZATION
 
+/*
+  Uncomment this to enable Teensy 3 I2C-Library i2c_t3
+  This can/should be used for Teensy >= 3 and Teensy LC.
+*/
+// #define U8X8_HAVE_HW_I2C_TEENSY3
 
 /* Assumption: All Arduino Boards have "SPI.h" */
 #ifndef U8X8_NO_HW_SPI