Cherry-pick "Merge branch 'BATIncrementalBuildFix-1.0-20180921' into '1.0'" into master

BAT/KLFitter Incremental Build Fix, 1.0 branch (2018.09.21.)

See merge request !347 (merged)

(cherry picked from commit 3a72823b)

• 7d5506bb Fixing the re-download/re-build of BAT.
• 6c093e2c Added a forcedownload build step for KLFitter.
• a15fb133 Added a forceconfigure step to KLFitter.