ENH: Centralize DIY setup logic in DIYEnvironment

This commit adds a new DIYEnvironment class wherein
all the logic to setup DIY is centralized to simplify
the code in InSituAnalysisManager.
ENH: Centralize DIY setup logic in DIYEnvironment

This commit adds a new DIYEnvironment class wherein
all the logic to setup DIY is centralized to simplify
the code in InSituAnalysisManager.

From: George Zagaris <george.zagaris@kitware.com>

git-svn-id: https://svn.alcf.anl.gov/repos/DarkUniverse/hacc/trunk/cosmotools@1902 952bdfbe-fa2e-45c0-a9ae-ac90d4a62daf
Merge branch 'svn/trunk'