http server brotli support

this release has the following content:
 1) brotli support in http server for html_run node
 2) small fix in builder drag and drop url display
 3) it now finds gameapi_display.zip from linux /usr/share dir if installed via deb package
4) o_to_ml that can do colourful voxels
5) perf optimization when browser calls our render callback twice per frame