Variable base path construction

[SMartorelli]

Change-log

• The variable base path construction for the excludedPathsList and allowedPathsList configuration profile keys has been enabled. This allows admins to define the base path of URLs they want to exclude or allow using $HOMEFOLDER and $APPFOLDER. If the tag is missing, the app will automatically consider the user’s home folder as the base path.

Closes #17

Pre-launch Checklist

• I read the Code of Conduct and followed the process outlined there for submitting PRs.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I updated README.md file with new version/info - if applicable.
• I added new tests to check the change I am making or feature I am adding, or Hixie said the PR is test-exempt.
• All existing and new tests are passing.