Define `rake test` as default rake task.

Contributors are used to execute just `rake`
on new projects. Help them :-)
Merge pull request #2 from splattael/default-task

Define `rake test` as default rake task.
Update README with simplified way of running specs
Swap params for `match` expectation.

Before this fix running tests gives:

    1) Error:
  expect syntax#test_0023_supports wont_match as to_not_match:
  TypeError: no implicit conversion of Regexp into String
      (eval):8:in `wont_match'
      (eval):3:in `to_not_match'
      /opt/ps/devel/_private/minitest-spec-expect/spec/integration_spec.rb:100:in `block (2 levels) in <top (required)>'

    2) Error:
  expect syntax#test_0022_supports must_match as to_match:
  TypeError: no implicit conversion of Regexp into String
      (eval):8:in `must_match'
      (eval):3:in `to_match'
      /opt/ps/devel/_private/minitest-spec-expect/spec/integration_spec.rb:96:in `block (2 levels) in <top (required)>'

Reason:

  "fartfartfartfart".must_match(/(fart)*/)

works while

  /(fart)*/.must_match "fartfartfartfart"

fails.

See also
https://github.com/seattlerb/minitest/blob/54fd3982/test/minitest/test_minitest_spec.rb#L431-443
Merge branch 'fix-match-pull-request' (via @splattael)
Allow passing block to `expect`.

After this commit this is possible:

    expect { raise RuntimeError }.to_raise RuntimeError

which is close to what rspec-expectations does:
https://github.com/rspec/rspec-expectations#expecting-errors