Add options to cccheck to find source in a different location

[yaakov-h]

cccheck currently reads the paths to source files out of the PDBs. This is required for some suppressions to work, e.g. RequiresAtCall.

What I need to be able to do for distributed testing is build in one path, e.g. C:\Build\MyProject, and then invoke cccheck from another computer entirely in a different path, e.g. C:\Testing\TestRun001\MyProject.

This pull request adds two command-line flags.

• -sourcePaths lists partial paths that the project was built from.
• -alternativeSourcePaths lists alternative/substitute paths that can be used to replace a partial path from -sourcePaths.

For example, with these changes I can successfully test an assembly in the scenario above by running:

C:\Testing\TestRun001\MyProject\bin\CodeContractsDeclarative>C:\path\to\cccheck.exe @MyProject.rsp -sourcePaths:C:\Build\MyProject -alternativeSourcePaths:C:\Testing\TestRun001\MyProject

If you don't supply both -sourcePaths and -alternativeSourcePaths, these changes have no other effect.

This goes hand-in-hand with #459.