add support for aliasing license types to existing licenses

use that to add support for license types matching exactly the creativecommons.org URL-s
fix eLife plugin + make it a bit more robust
minor enhancement (deduplicate effort) to URL cleaning used all over the system
finally clean up URL-s correctly - clean base URL-s recorded in plugins as well as the URL-s of incoming identifiers
strip www. from URL-s by default everywhere - all content plugin tests pass
preserve newlines in plugin descriptions when displaying them to the public
remove old test from script which runs all content plugin tests since it tests the PLOS plugin which no longer operates .. it is the tutorial test unfortunately so the file has to be kept, but anybody following the tutorial will change the values since they will be testing some new plugin, not PLOS
new sciencedirect plugin