TEST - Fixes case where exception is raised in parameter function

In get_parameter_values, if an exception is raised the exception is encapsulated in a ParameterFunctionException and reraised. This allows clients to handle exceptions on a per-parameter basis, and for the case of retrieve we just don't fill in the values and log the error. Using get_value_dictionary on the other hand is a bit trickier. This patch fills in an array of fill values and logs the exception.
Merge pull request #148 from ooici/fix

TEST - Fixes case where exception is raised in parameter function
Removes exc_info from logging exception
Merge pull request #150 from ooici/velfix

Removes exc_info from logging exception
Merge branch 'master' of https://github.com/ooici/coverage-model into HDFtoDB

Conflicts:
	coverage_model/coverage.py - Simple import conflict.