failure to parse params should trigger a 400 Bad Request
Improve poor security recommendation in docs

As reported in #9960, the current documentation recommends an insecure practice for
key generation from a password (a single round of SHA-256). The modified documentation
uses ActiveSupport::KeyGenerator to perform proper key stretching.
Fixes skipping object callback filters

This allows you to skip callbacks that are defined by objects, e.g. for
`ActionController`:

    skip_after_filter MySpecialFilter

Previously this didn't work due to a bug in how Rails compared callbacks
in `Callback#matches?`. When a callback is compiled, if it's an object
filter (i.e. not a method, proc, etc.), `Callback` now defines a method on
`@klass` that is derived from the class name rather than `@callback_id`.
So, when `skip_callback` tries to find the appropriate callback to
remove, `Callback` can regenerate the method name for the filter
object and return the correct value for `Callback#matches?`.
Fix loading of string arrays in postgres
options_from_collection_for_select helper takes html attributes

as the last element of the array
Use strip_heredoc where possible

Following up on an observation by @rafaelfranca

https://github.com/rails/rails/pull/10170/files#r3753963

Reduce the number of gsub calls to the two cases where inputs are concatenated
from various sources and with inconsistent indentation.

Also zap extraneous spacing from the sass-rails line... presumably this is a
holdover from a previous time where this aligned the version string with an
adjacent line.
Changed grammar for better readability
ARel -> Arel
Added description for mtime
Updated link to peepcode Git screencast
Tried to make the response status code table more readable

By making it the last thing in it's section and adding pseudo row headers
Fixed typo [ci skip]
Clarify arguments of head method
Align table of HTTP status codes with set supported by current Rack
added a test suite for the postgres binary type
this shows a problem with nil values
fix for the bytea/binary nil value bug
Ruby 1.9 hash syntax for action controller guide
more Ruby 1.9 Hash syntax in our guides
interpolate instead of string concat
Merge pull request #10220 from vipulnsward/interpolate_on_string

interpolate instead of string concat