ESP8266 board package compatibility update

Board core package 2.5.1 and 2.5.2 compatibility update.

Bug fixes for smooth font rendering

1.4.8

Fix bug in UTF-8 line buffer decoder

Fix touch functions for ESP8266

Fix touch screen handler

The touch screen handler was broken for the ESP8266 only. The library
uses SPI write only configuration for ESP8266 so the SPI buffer can be
recycled and it was left in write only mode. The library now switches
back to read & write mode at the end of a transaction.

Fix new bugs in 1.4.3 and expand GFX font capability to 16 bit Unicode

1.4.4

Raise issue in header

New functions and examples added

1.4.3

Remove screen server code

Correct RPi display strobe timing

Strobes for other displays are kept fast.

Corrected error in header

1.3.7

Update

Added WROVER ST7789 support

Update for WROVER to address #232

The library supported 240x240 ST7789 displays only which require an 80
pixel offset in rotation 2 and 3
The library now also supports the 240x320 display which has a different
RGB colour order.

Added 160x80 display plus bug fixes

Merge pull request #179 from tablatronix/160x80_BGR

160x80 bgr

Add new examples

Added new anti-aliased font rendering examples.