Allow additional freemarker template loaders to be injected
Move RequestContext creation into ExplorerManager so that it can be customized
Moved building of main FTL template path into RequestContext so that it can be overridden
allow config instance to be overidden
Make loadPropertiesFileFromForms() overloadable
Support basehref
Merge pull request #1 from Randgalt/master

Changes to allow customizing how Explorers are determined/allocated