fix Data Mapper test assertion
test against Rails 4.0.0.rc2 and Rails 4.1 (edge)
Exclude reorder for count queries.

It turns out reorder behaves differently on Rails 3.1 and requires
explicit exclude to not pollute count query with order clause.
Rails 4 compat: AR::Base.silence requires an argument
Rails 4 compat: port named scopes to new syntax

Subtle edge case bugs pop up in AR 4 when named scopes are declared with
the old syntax. This is likely a bug with AR, but work around it for now.
don't build Rails 4 against Ruby 1.8, 1.9.2
add license information to gemspec

[ci skip]
always call `html_safe` on will_paginate result

This ensures that the HTML output of `will_paginate` view helper is not
only marked safe in Rails, but in Padrino as well.
clarify that the library works with Rails 4 as well

[ci skip]
Support paginate(:total_entries => n) for dm
Merge pull request #358 from phuesler/dm_total_entries

Support paginate(:total_entries => n) for DataMapper
Accept arguments for Relation#count