This handler simply allows arbitrary Ruby code as a template

Add automatic template digests to all CacheHelper#cache calls (originally spiked in the cache_digests plugin) *DHH*

Related with 5e7d6bba

When using compute_source_path to determine the full path of an
asset, if our source begins with '/', we don't want to include
the directory. Examples are illustrative:

> compute_source_path("foo", "stylesheets", "css")
=> "/Users/steve/src/my_app/public/stylesheets/foo.css"
> compute_source_path("/foo", "stylesheets", "css")
=> "/Users/steve/src/my_app/public/foo.css"

Before this patch, the second example would return the same as the
first.

Fixes #5680.

When more than one directory for helpers is provided to a controller, it
should preserver the order of directories. Given 2 paths:

    MyController.helpers_paths = ["dir1/helpers", "dir2/helpers"]

helpers from dir1 should be loaded first. Before this commit, all
helpers were mixed and then sorted alphabetically, which essentially
would require to rename helpers to get desired order.

This is a problem especially for engines, where you would like to be
able to predict accurately which engine helpers will load first.

(closes #6496)

Fixes #2394

Allow access to current object_counter variable from layout when rendering with partial + collection

config.action_view.prefix_partial_path_with_controller_namespace

This allows you to choose to render @post using
/posts/_post.erb instead of /admin/posts/_post.erb
inside Admin::PostsController.

Previously `rendered_format` was set only based on mime types
passed in Accept header, which was wrong if first type from
Accept was different than rendered partial. The fix is to simply
move setting rendered_format to the place where template
is available and grab format from the template. If it fails
we can fallback to formats passed by Accept header.

Fix for #5440

Closes #5025 part 2

Closes #5025

Windows doesn't allow `\ / : * ? " < > |` in filenames so create
the fixture files at runtime and ignore the incompatible ones when
running on Windows.

RFC 3986[1] allows sub-delim characters in path segments unencoded,
however Rack::File requires them to be encoded so we use URI's
unescape method to leave them alone and then escape them again.

Also since the path gets passed to Dir[] we need to escape any glob
characters in the path.

[1]: http://www.ietf.org/rfc/rfc3986.txt

Fix fragment caching (squashed commits)

For example, calling hello.erb is now deprecated. Since Rails 3.0
passing the handler had no effect whatsover. This commit simply
deprecates such cases so we can clean up the code in later releases.

it is now possible to pass details options (:formats, :details, :locales, ...) to #render, #find_template and friends. this doesn't change anything in global context.