Initial, naive introduction of servlet Marketplace access.

Renders.  Unstyled.  De-featured as regards links.
Abuses the existing `/api` scoped Servlet MVC context.
Brute force first pass styling for Marketplace servlet JSPs.
Document new org.jasig.portal.web.servlet package.
Exclude org.jasig.portal.web.servlet from applicationContext component scanning.

It's scanned in the MVC context.
Remove stray duplicate `htmlEscape` declaration.
Remove unused getters for Marketplace Service and Portlet controller properties.
Remove unused getters for MarketplaceServletController properties.
Merge pull request #312 from apetro/marketplace_servlet_initial_progress

Marketplace servlet initial progress