This reverts commit f6ba7b06.

This reverts commit b659eb25.

Reduce number of std container copies in environment settings code along with a few cleanup nitpicks from intellisense

Original commit in Nat's repo: https://bitbucket.org/lindenlab/viewer-vs2017-git/commits/f627140cf11232bab11fdfaf66c78544cf44f3e8

There are duplicate LLTrace::BlockTimerStatHandle key strings declared in
llsettingsdaycycle.cpp and llsettingswater.cpp -- the only instances of
duplicate BlockTimerStatHandle keys in the viewer code base. SL-13467 tracks
intentional crashes due to duplicate LLInstanceTracker subclass instances with
one of those keys. The simplest experiment to try to eliminate those crashes
is to ensure that every BlockTimerStatHandle in the code base is unique.

SL-10499 - benefits. Removed no-longer-needed lleconomy files and classes. Group-related costs and limits via benefits.

Remedy cloud_shadow and hack halving being done twice to ambient in some cases (i.e. artificial dimunition of necessary bullshit factor).

Fix false alarming sky updates and doing expensive CPU work for same sky pixels.