Tests of cache types for EDProducer, EDAnalyzer and EDFilter in the edm::global,edm::stream and edm::one namespaces
Thread safe Xerces-C setup / termination.

See http://xerces.apache.org/xerces-c/faq-parse-3.html#faq-6 for the limitations
on Xerces-C.
Updates
Merge pull request #924 from ktf/thread-safe-xerces-c

Thread safety -- Thread safe Xerces-C setup / termination.
Use UnsafeCache for Run and LumiBlock summary
use bool instead of Cache to get globalBeginRun, globalBeginLuminosityBlock, etc
Note edm::stream::RunCache<void> and edm::stream::LuminosityBlockCache<void>
do not work in the BeginRunProduce, BeginLuminosityBlockProduce context
Merge pull request #920 from gartung/test-edm-cache-templates

Multithreaded framework -- Tests of cache types for EDProducer, EDAnalyzer and EDFilter