Update README to point out 2 caveats with scopes and

provide Gemfile info for using branches.

Minor example code change.

[skip ci]
Revert "Update README to point out 2 caveats with scopes and"

This reverts commit cde3e0e6f2bf4dcf65d27f06f202c82ae57ea100.
Update README to point out 2 caveats with Scopes and

provide Gemfile info for using branches.

Minor example code change.

[skip ci]
Add multiple sort field support in sort_link

This patch allows users to sort on multiple fields with the sort_link
helper.

To specify sorting on multiple fields:

  sort_link(:kind, [:kind, 'name asc'])

This will create a sort link that sorts first by kind, and then by
name. The first `:kind` parameter ensures that the link generated
shows the sort status of the `kind` field.

When you specify a sort direction in the sort fields array, the
direction is locked to that direction. In the above example, clicking
the resulting link would toggle sorting of the kind field, but the name
field would always sort ascending.

Also added was the ability to specify multiple default_order fields
with a hash:

  sort_link(:kind, [:kind, :name],
            :default_order => { :name => 'asc', :kind => 'desc' })

Clicking the resulting link will toggle the sort directions of both
`name` and `kind`, sorting the `name` field by default ascending, and
the `kind` field descending.
Add spec for providing an override label

This spec ensures that the user can provide a label when specifying
multiple sort fields
Merge pull request #438 from caleb/multiple-fields-sort-link

Add multiple sort field support in sort_link [skip ci]
Follow-up to #438, green tests for Rails 3.1 / 3.2
Improve scopes documentation in README

[skip ci]
Update Change Log: multiple sort fields [skip ci]
Follow-up to last commit [skip ci]
Helpers::FormHelper: clean up, extract method, rename.
Memoize repeated Hash === conditional
Reduce object allocations and speed up Ransack by

extracting commonly used strings into top level Ransack
constants.
Reduce object allocations in Ransack::Nodes::Sort

`try` allocates an array on every call; we should avoid calling
it in hotspots.
Add more examples of sort_link to README [skip ci]

Added an example of sorting on multiple fields with `sort_link`
Merge pull request #439 from caleb/multi-sort-link-readme

Add more examples of sort_link to README [skip ci]
Update Change Log [skip ci]
Merge branch 'master' of https://github.com/activerecord-hackery/ransack
Update README about new sort_link features

and improve/simplify the first examples.

[skip ci]
Simplify sort_link code examples in README docs.

[skip ci]