Rear view zoom level

new zoom icons
save and restore state from settings
display zoomed out rear view when selected
Merge branch 'master' of https://github.com/worklist/hifi into 19447

Conflicts:
	interface/src/ui/RearMirrorTools.cpp
Merge pull request #1141 from stojce/19447

Code Review for Job #19447
Looks like setCentralWidget is ending up calling the init functions in newer
versions of Qt.  Initialize the network access manager before that happens.
Merge pull request #1147 from ey6es/ick

Support for normap maps on loaded models.
Merge pull request #1149 from ey6es/master

This should fix Stephen's crash on init.