require timeout in tests

When running "testrb test/test_rails_autolink.rb", the test suite fails:

  NameError: uninitialized constant TestRailsAutolink::Timeout

Explicitly load the timeout gem during the tests to fix this error.
Fixed typo + added word.

Not a big issue, but just fixing typo's!
refactor Gemfile/tests to revive ability to run against Rails 3.2.x, 4.0.x, 4.1.x

* simplify required modules for tests to avoid version-specific breakage because of internal Rails refactoring
* Gemfile has notes on dependencies - it's not automatic
* mintiest pegged down for Rails 3.2.x to avoid assert_dom_equal issue
* if rails_autolink/helpers included before action_view/helpers, it was obscuring helper methods
make test_auto_link_email_addres_with_especial_chars work on Rails 3.x
 
* original from pull request #31
hold onto trailing = and & as part of urls
Fixed a potential XSS by link attributes
Merge remote-tracking branch 'evendis/hold_onto_trailing_cruft'
ignore rvm/rbenv initialisers
make test the default rake task
Merge remote-tracking branch 'fcsonline/fix/xss-inline-attr'