assets option from the old stylemark is missing in the new stylemark

[mbehzad]

lsgAssetsSrc was removed with the note: "... pv-scripts users can just use the resources folder". The issue with that is that the resource directory is meant to be part of the clientLibraries and will be deployed to the production. And shouldn't contain styleguide specific content.
PR #226 will add the stylemark's assests option back, which can be used for any icons, css, etc that is needed only for the styleguide.

[friewerts]

see comment in PR