Fix contain_match, add none_match

[alexpop]

Other changes:

• update matchers doc and add more integration tests
• allow non-string data types and non-arrays

contain_match was incorrectly reporting success for a test like this:

describe ['lemon', 'ginger', 'grapes'] do
  it { should contain_match /^ginnnnnnnnnnnn/}
end

[chris-rock]

I like the addition of the none_matcher