TODO: the neuronnameDisplay has to move out of stack.js and into tracingtool.js
webglapp: skeleton text tags are not created by default but on demand.

Fixed error in creating text tags, was only creating one single tag
of each kind instead of as many as necessary.

Found accidental global variables (camera, sphere) and made them local.

Fixed error in variable name "ambienteLight", now there is an ambient light.
Merge remote-tracking branch 'origin/master'