Fixed test "ArgumentError: wrong number of arguments(1 for 0)"

warning removed "warning: instance variable @variable_for_layout not ini...

Fix expanding cache key for single element arrays

Fixed bug when error message is an empty string.

Fix favicon_link_tag help text

In short:
expand_cache_key(element) should not equal expand_cache_key([element])

This way a fragment cache key for an index page with only a single
element in the collection is different than a fragment cache for a
typical show page for that element.

Allows two models to use the same table but have different primary keys.

Warning removed "warning: (...) interpreted as grouped expression"

Move delegation reponsibilities of Relation to a module. Also precompile method missing calls for rofscale.

Small typo in Rails::Engine documentation