branching off 0.11 for work on stampede protection
more work on stampede protection, refs #744
added stub abortedCacheCreationCallback and adjusted callback signatures, refs #744
merge 94b32e1dfdf4555cb4c88782016bb5fff9ec62e8
merge e70c4351d2c1e9901da1fe6c7c209647411cb11d...acfcbfc3b203e77e797cc90d561aba30ecd53f45 (from 0.11)
merge da245f80411c8944bd3295cea33f999f65bb455e...9faa34d7f0d527486078bc84b8f5e49fa7c0231e (from 0.11)
merge d0146bea2faa6a7ab8e324ef411c4f0635a5adc0...f7a7e70485ff1dc4a8e2fc105fd06fbdae6619c6 (from 0.11)
merge 236f6c9b4b08d9dd7c6880c745809c949ca52baa...809e3fe01e11a84a48c057eefef18d926ac1224a (from 0.11)
merge [2601:3543/branches/0.11]
porting branch to 1.0
set lock only if action is cacheable
release stampede lock on view when execution needs to start over in case action is cached, but view isn't
merge 4742d78a7c7882b06909e4164a5510975e62fc7b...c647135c295bb983f5517bc1188c41363f84e1b4 (from 1.0)
dox
hand action groups, not view groups (they don't even exist) to aborted... callback if output type is not cacheable
Merged support for anti-stampede callbacks in Execution Filter (from 0f7d32764251ed3f701e6177c09dbf1dc269a3f6...e7a98698fbf27740a0966f2ae9fa0ead45a601fe (from david-stampede_protection)). Example implementation to follow. Closes #744