implemented term negation
fixed string comparison bug on ruby 1.8.7
Added a tsearch-specific :negation option to enable term negation
Convert specs to RSpec 3.0.4 syntax with Transpec

This conversion is done by Transpec 2.3.7 with the following command:
    transpec

* 6 conversions
    from: it { should ... }
      to: it { is_expected.to ... }

* 3 conversions
    from: == expected
      to: eq(expected)

* 1 conversion
    from: it { should_not ... }
      to: it { is_expected.not_to ... }

For more details: https://github.com/yujinakayama/transpec#supported-conversions
Add binstubs for guard and spec
Use rspec binstub in guard-rspec
Set null: false on timestamps calls

To avoid deprecation warning in Active Record 4.2
Fix future compatibility with Active Record 4.2

Use Arel::Nodes.build_quoted to quote strings if present, otherwise fall back to preexisting behavior.
VERSION 0.7.7
Don't include binstubs as binaries in the gem
VERSION 0.7.8
Remove coveralls badge

It was lying about our test coverage and making us look bad.
Do not save already destroyed pg_search_document.

This can happen in case of complex associations and callbacks, when
destroying associated objects results in model.save being called from
after_destroy hook.
Merge pull request #118 from derek-watson/master

Implemented simple negated terms

Conflicts:
	lib/pg_search/features/tsearch.rb
	spec/lib/pg_search/features/tsearch_spec.rb
Add test for when options[:negation] is false

#118
Add integration test coverage for negation

re: #118
Add documentation for :negation

re: #118
Test against latest versions of Ruby 1.9, 2.0, 2.1
Add 4-2-stable to tested branches of Rails
Merge branch 'negation'

Closes #118