Fixes queries using limits and punctuation in order, removes order("col1, col2") usage in favor of order(["col1", "col2"})

[#4597 state:committed]

Allowing to_xml :camelize option to be set to :lower to enable lower-camelcase tags [#5903 state:resolved]

Signed-off-by: NAndrew White <andyw@pixeltrix.co.uk>

Also remove a duplicate test_link_to_unless assertion and add .html_safe to the
remaining one.
Signed-off-by: NSantiago Pastorino <santiago@wyeworks.com>

* Hypertext Transfer Protocol -- HTTP/1.1
  http://www.ietf.org/rfc/rfc2616.txt)

* HTTP Extensions for Distributed Authoring -- WEBDAV
  http://www.ietf.org/rfc/rfc2518.txt

* Versioning Extensions to WebDAV
  http://www.ietf.org/rfc/rfc3253.txt

* Ordered Collections Protocol (WebDAV)
  http://www.ietf.org/rfc/rfc3648.txt

* Web Distributed Authoring and Versioning (WebDAV) Access Control Protocol
  http://www.ietf.org/rfc/rfc3744.txt

* Web Distributed Authoring and Versioning (WebDAV) SEARCH
  http://www.ietf.org/rfc/rfc5323.txt

* PATCH Method for HTTP
  http://www.ietf.org/rfc/rfc5789.txt

[#2809 state:resolved] [#5895 state:resolved]

only returning where values for the corresponding relation, also filtering where value hash based on table name [#5234 state:resolved] [#5184 state:resolved]

Convert :primary_key in association to a string before comparing to column names, so that for example :primary_key => :another_pk works as well [#5605 state:resolved]

Refactoring: replace the mix of variables like @finder_sql, @counter_sql, etc with just a single scope hash (created on initialization of the proxy). This is now used consistently across all associations. Therefore, all you have to do to ensure finding/counting etc is done correctly is implement the scope correctly.

We saw a failing spec when running the DataMapper
ActiveModel compliance specs for dm-active_model.

  ActiveModel::Naming#model_name

relies on the Module#parents method defined in

  active_support/core_ext/module/introspection.rb

Adding the appropriate require statement of course
fixed our specs.