Removed Invoke-Expression from DscConfiguration module's Get-Hashtable function

This function is essentially a duplicate of Import-DataFile in the DscBuild module.  Not sure if we want to extract common code into a separate module that is loaded up by both DscBuild and DscConfiguration, or just live with the slight duplication.
Bumped version numbers of DscConfiguration and DscBuild
Added additional options for configuring Certificate ID in DscConfiguration

Module import arguments aren't particularly discoverable; added functions and parameters to bring this option into parity with the configuration data path.  (Can be specified at module import time, when calling Get-DscConfigurationData, or by calling Get / Set commands for the option directly.)
Improved overall error handling and reporting of encryption-related code

There was some inconsistent use of terminating versus nonterminating errors, and potential problems with null reference exceptions in finally blocks; these have been cleaned up.
Merge pull request #85 from devopsguys/ToolingUpdates

Improvements to DscConfiguration module