TC: 'external' templates now publically accessible (externally)

See previous commit. External templates can be accessed without a
session via direct browser/path (i.e. not inside the ExtJS client).

This may be expanded later to provide finer-grained control (i.e. with a
'public_tpl' permission that might apply by default to 'external_tpl'
templates)

Also modified some of the Controller function lookups to cache in the stash
(persist throughout the request). This was done for performance for
lookups that now happen multiple times during a single request. This may
also be expanded/better generalized