Add default ctors
Ignore minor precision differences in test.

The test which uses ProducerWithPSetDesc was failing under gcc490
because python and C++ disagreed on the value of double(0.3) on the
last bit in the precision. The test was changed to accept a tolerance
of 1E-6.
Merge pull request #2485 from Dr15Jones/avoidPrecisionProblemInTest

Misc fixes -- Ignore minor precision differences in test.
Merge remote branch 'origin/CMSSW_7_1_X' into CMSSW_7_0_X
Merge pull request #2486 from wmtan/AddDefaultCtors

Add default ctors
Add missing include of iostream
Merge pull request #2488 from wmtan/AddMissingIOstreamInclude

Add missing include of iostream
Merge pull request #2487 from wmtan/AddMissingIOstreamInclude

Misc fixes -- Add missing include of iostream
Merge remote branch 'origin/CMSSW_7_1_X' into CMSSW_7_0_X