Merge branch 'master' of https://github.com/worklist/hifi into 19495
Basic LRU cache.  Closes #2234.
Merge branch 'master' of https://github.com/highfidelity/hifi into metavoxels
Better merging for normals.
Some untested ray intersection bits.
Applied Ryan's tweaks to Visage mapping and config file.
Slight tweak to Visage instructions (in order not to overwrite our custom
configuration).
Merge branch 'master' of https://github.com/highfidelity/hifi into editVoxels
remove space bar behavior from editrVoxels.js
Remove spanner bits.
remove qt5 homebrew formula - it lives at highfidelity/homebrew-formulas
update the BUILD guide to point to the new formula location
Merge pull request #2259 from birarda/master

remove homebrew formula to place in separate repo
Merge branch 'master' of https://github.com/highfidelity/hifi into metavoxels
updates to BUILD for addition of qxmpp
clarify when it is possible to drag-and-drop external dependency
Ray intersections for models, don't load resources if there's no network
manager installed.
Merge pull request #2258 from ZappoMan/bugfixes

remove space bar behavior from editrVoxels.js
resolve conflicts on merge with upstream master
updates to BUILD guide to suggest using tapped formulas