the select method (tag select) forces :include_blank  if is required and no multiple and
display size is one

and display size 1 and not multiple attribute,  Fixes #5908

Fix NumberHelper options wrapping to prevent verbatim blocks being rendered instead of line continuations.  While I'm at it, wrap long comment lines consistently.

Adding test for humans.txt

add humans.txt

Allow explicitly set content-type via head method when status code allows it according to the RFCs

Add failing test re #3436 which demonstrates content_type is not respected when using the :head method/shortcut

Removed ActiveSupport#load_all!

Fix guides for as core ext

This reverts commit c962680e.

Reason: The links must be relative to work in both edge and stable api
sites.

Revert "Compressed all images from the guide through ImageOptim which saves sometimes up to 74.6% in size [ci skip]"

Reason: this change can't really be done in docrails,
see http://weblog.rubyonrails.org/2012/3/7/what-is-docrails/

This reverts commit bc06e8d7.

Locking ruby-prof for now. 

Minor test improvement

Compressed all images from the guide through ImageOptim which saves sometimes up to 74.6% in size [ci skip]