Change Rubygems source url to use HTTPS
Rename method
Implement generate_history method in every SCM
Substitute if-else block with `detect` method
Simplify string quotation inside the gemspec

Now it just uses double quotes instead of the %q notation.
Make use of Hash default value
Extract file rejection into two different methods
Substitute `match` method for the `=~` operator

The `match` method generates a MatchData object, making it slower than
the `=~` operator [1]. Since this MatchData object is not being used, it
makes sense to switch to `=~`.

[1]: http://stackoverflow.com/a/11908214/1160916
Fix testing on Ruby 2.1.2

Changes include:

* Using Minitest::Test instead of Test::Unit

* Updating mocha to the latest version

* Using test_construct since test-construct is no longer being maintained

* Fixing 3 broken tests
Update Travis config to test Ruby 2.1.2
Use Travis' new SVG badge
Fix whitespace
Merge pull request #49 from guilhermesimoes/refactoring

Code refactoring