Take care of whitespaces and changing the hash syntax
descriptive `assert_template` error when partial wasn't rendered

When `assert_template` is used with the :locals option, and the
partial was not rendered, a method_missing error was raised.
This changes first checks, if the partial actually was rendered
and raises a descriptive error.
partials inside directory work with `assert_template`

previously when a partial was placed inside a directory
(eg. '/dir/_partial'), `assert_template` did not replace
the '_' prefix when looking through rendered tempaltes,
which resulted in an error.

I modified it to replace both, the leading '_' and the last '_'
after a '/'.
Merge pull request #8520 from senny/8516_assert_template_with_locals

Improved `assert_template` when matching :locals with partials
Use --rc= instead of --rc
Merge pull request #9174 from robertomiranda/railsrc-cli-option

Use --rc=PATH instead of --rc PATH
Add --rc description on the command line
Merge pull request #9175 from robertomiranda/add--rc-desc

Add --rc description on the command line
Added test:all and test:all:db tasks to speed up full test runs.

Speed up depends on the number of test phases (N) you have for your
app, but it is roughly a 1/N improvement. In my app, it goes from
15.51s to 5.56s.

Inspired by http://ngauthier.com/2012/02/quick-tests-with-bash.html

Reviewed by @tenderlove
Merge pull request #9177 from zenspider/master

Added test:all and test:all:db tasks to speed up full test runs
Update upgrading guide with ActionDispatch::BestStandardsSupport removal
Merge pull request #9178 from robertomiranda/best-standard-support-guide

Update upgrading guide with ActionDispatch::BestStandardsSupport removal [ci skip]
Ignore .ruby-version
Merge pull request #9192 from adammck/ignore-dot-ruby-version

Ignore .ruby-version
Enable hstore extensions on tests if it is not enabled and database supports it
Update .gitignore

Get rid of old .rvmrc and .rbenv-version files.
ruby constant syntax is not supported as routing `:controller` option.

The current implementation only works correctly if you supply the `:controller`
with directory notation (eg. `:controller => 'admin/posts'`).

The ruby constant notation (eg. `:controller => 'Admin::Posts`) leads to unexpected problems with `url_for`.

This patch prints a warning for every non supported `:controller` option. I also added documentation how
to work with namespaced controllers. The warning links to that documentation in the rails guide.