* added multibyte handling for string assertions and the ability to set an encoding for all string functions
* added some unit tests for some multibytes
* added ext-mbstring as requirement to composer.json
Removed the UTF-8 option as a class level state to avoid the possibility to override the encoding
Removed the UTF-8 option as a class level state to avoid the possibility to override the encoding
the encoding now is an optional parameter for all string relevant assertions
* the encoding now is an optional parameter for all string relevant assertions as the last parameter
* removed the sentence indicating that the ```$message``` parameter must be the last one
* added some testcases to test encoding issues
Merge pull request #12 from gruberro/mbstring

String regarding assertions should handle multibyte strings too
Implemented: added ability to assert the implementation of a specific interface
Documented: added new assertion to the list of assertions
Fixed: corrected naming of the arguments to be a better fit to the librarys pattern.
Merge pull request #15 from lapistano/implementsInterfaceAssertion

Implements interface assertion
Implemented assertion to verify urls using the filter_var() function of PHP
Refactored: beberlei pointed me to some strange behaviors of filter_var(). So I adapted SF2 code for a more secure assertion.
Merge pull request #19 from lapistano/moreAssertions

Implemented assertion to verify urls using the filter_var() function of PHP
Completed Assertion list, fixed docblocks
Merge pull request #20 from raphaelstolt/docblock-readme

Completed Assertion list, fixed docblocks
Make travis run the tests
Merge pull request #21 from raphaelstolt/travis-phpunit

Make travis run the tests
Make travis really run the tests
Merge pull request #22 from raphaelstolt/travis-phpunit-composer

Make travis really run the tests
Implemented ability to verify that the given value is not an instance of the provided one