Update release date estimate in README
Merge branch 'master' of github.com:acgessler/open3mod
Fix setting of light direction.
Tweak ambient lighting.
#Fix Scrolling of Material and Texture Tabs
Make light source rotateable (move mouse while having the right  mouse key pressed).
Configurable light intensity / brightness.
#Fix crash on empty tab

Add the ability to change the behaviour when you close the last tab:
- Either a new empty tab is added
- or the whole application exits
Add setup project with basic setup flow.
#Fix crash on too small viewport

Viewport has now a minimum size
Setup: use relative paths.
Add Hiding of Viewport Borders in Single Viewmode
Setup: add EULA/license file.
#Fix Hide Unused Viewport Separators

In Single and Two Viewmode hide the Separators that are not usable
Change copyright info to "Open3Mod Contributors", add Contributors file.
Merge with acgessler/open3mod/master
MaterialPreviewRenderer: set proper GL z and matrix state instead of relying on previously set values.
Visualize light source, transform light into viewspace.
Also update fixheaders.py script with new copyright info template.
Improve light rotation.