Fixes TravisCI shield to point to the correct branch buildroot, removes no longer used shield and adds some new shields.

5-axis, high performance, powerful board with Smoothieware opensource firmware. Designed for 3D printer, Laser cutter or CNC mill. Five changed independent drivers on board. Two extruders 3d printer support.

* Add Azteeg X5 GT to supported list

Signed-off-by: Alexey Shvetsov <alexxy@gentoo.org>

* Update README.md

LCD call was waiting forever, causing the system to hang.

Sync with RC8

・Change "RC6" to "RCBugFix" on top part of the readme
・Unify distribution date of RCBugFix and RC6
・Move comments about IDE version from RCBugFix section to RC6 section

It sync with the RC.

follow-up to commit 200b2487

Update release date in another place

Oops! at least 1.6.0

* Description for RC5
* Hint for deprecated Arduino versions