Update to three r184

[vincentfretin]

To do for @dmarcos :

• create the super-r184 branch, you can get the commits from https://github.com/vincentfretin/three.js/tree/super-r184-vf (I cherry-picked from super-r181 and resolved the conflicts)
• merge Remove pcfsoft shadow type, deprecated in r182, pcf is now soft as well #5798
• merge Replace Clock instance by Timer instance (three r183+) #5800