refactor the naming within plugin new generator

Having a method called `full?`, which checks on :full and :mountable
is very confusing. I renamed `full?` to `engine?` and created a `full?`
method that only checks the `:full` option
change spy of  after invoked controller action. because ruby-2.0.0 waned unused variables
Eager loading made to use relation's in_clause_length instead of host's one (fixes #8474)
Remove warning of intance variable not initialized
Add rake default to description
Add rake test description
reminder to run bundle after setting up rails-dev-box
chmod -x from non-script files
Merge pull request #8601 from amatsuda/chmod_x

chmod -x from non-script files
fetch highlighter option only when needed
silences "possibly useless use of :: in void context" warnings

The AS utility silence_warnings does not really silence this
one, because it is issued at parse-time. It seemed to in
some places because the constant was the only expression in
the block and therefore it was its return value, that could
potentially be used by silence_warnings are return value of
the yield call.

To bypass the warning we assign to a variable. The chosen
variable is "_" because it is special-cased in parse.c not
to issue an "assigned but unused variable" warning in turn.
minor grammar fix
Merge pull request #8604 from zoltankiss/minor_fixes

minor grammar fix
Merge pull request #8592 from rafaelfranca/warning_fix

Remove warning of intance variable not initialized
ActiveSupport::BufferedLogger can be subclassed
Merge pull request #8607 from senny/8576_cant_inherit_from_deprecated_buffered_logger

ActiveSupport::BufferedLogger can be subclassed
deprecation warning when BufferedLogger is instantiated
replace AS::BufferedLogger doc mentions with AS::Logger
Merge pull request #8609 from senny/buffered_logger_documentation

replace AS::BufferedLogger doc mentions with AS::Logger
Merge pull request #8608 from senny/8576_cant_inherit_from_deprecated_buffered_logger

deprecation warning when BufferedLogger is instantiated