Update .travis.yml

Author: Dennis-van-Gils

.travis.yml

@@ -1,6 +1,8 @@
 language: python
 
 python:
+  - "3.6"
+  - "3.7"
   - "3.8"
 
 addons:
@@ -25,10 +27,10 @@ before_install:
   #conda install --yes python="3.8" pyqt;
   pip install -r requirements.txt
 
-  sudo apt-get install -y libdbus-1-3 libxkbcommon-x11-0
+  #sudo apt-get install -y libdbus-1-3 libxkbcommon-x11-0
 
 script:
-  - python demo_A_GUI_full.py simulate
+  #- python demo_A_GUI_full.py simulate
   - python demo_A_GUI_full.py
   - python demo_B_GUI_minimal.py
   - python demo_C_singlethread_for_comparison.py