r4188 was published on 2018-04-10 but lost after a sourceforge storage problem.
See for example https://sourceforge.net/p/forge/site-support/17420/
2.2.0a0 (unstable/experimental)
* sf.net/p/pymol/bugs/199 bash -> sh
* ignore zero-order bonds in neighbor lookup
* fix crash loading reduced 5ijo.mmtf
* volume panel: fix zoom (CTRL+R-Drag) and value input (R-Click)
* QOpenGLWidget support (not active by default)
* --gldebug -> backtrace on GL error
* stick_round_nub for COLLADA export
* UTF-8 in feedback
* display_scale_factor (ported from Incentive PyMOL)
* dx map import: support "type float" and skewed delta
