Starfield fix and Milky Way

Fixed bug where more stars were generated at the poles.

Added 'Milky Way' band in sky, customisable with MILKY_WAY_WIDTH,
MILKY_WAY_INCLINATION and MILKY_WAY_RATIO consts in Generator.cpp.
first cut at user adjustable LOD
first cut at user adjustable LOD
more work on LOD slider
make server resend scene when LOD changes
adjustable LOD tweaks
Merge branch 'master' of https://github.com/worklist/hifi into lod_slider
removed debug
fix one call to calculateShouldRender()
removed dead code
Merge branch 'master' of https://github.com/worklist/hifi into lod_slider
fix build buster
fix Voxel Server Protocol menu options to work again
fix voxels as points menu to work correctly on startup
improve behavior of too more than _maxVoxels
improve voxel server's behavior when client is moving, dump out of view pending voxels
added abandoned voxels to stats, improved sizing behavior of voxel stats dialog
if LOD changes than don't consider WasInView on server
Merge pull request #1148 from ZappoMan/lod_slider

LOD slider in client
If the skeleton has meshes, don't render the balls and sticks.