RFR: 8217472: Add attenuation for PointLight [v6]

[Nir Lisker]

> CSR: https://bugs.openjdk.java.net/browse/JDK-8218264

Nir Lisker has updated the pull request incrementally with three additional commits since the last revision:

 - Merge remote-tracking branch 'nlisker/8217472_Add_attenuation_for_PointLight' into
   8217472_Add_attenuation_for_PointLight
 - Addressed review comments
 - Addressed review comments

-------------

Changes:
  - all: https://git.openjdk.java.net/jfx/pull/43/files
  - new: https://git.openjdk.java.net/jfx/pull/43/files/2e1223ed..c5481066

Webrevs:
 - full: https://webrevs.openjdk.java.net/jfx/43/webrev.05
 - incr: https://webrevs.openjdk.java.net/jfx/43/webrev.04-05

  Stats: 34 lines in 7 files changed: 1 ins; 0 del; 33 mod
  Patch: https://git.openjdk.java.net/jfx/pull/43.diff
  Fetch: git fetch https://git.openjdk.java.net/jfx pull/43/head:pull/43

PR: https://git.openjdk.java.net/jfx/pull/43