add a trait for helping with expectations.

Permit this:

    $Foo
        ->expects($this->next())
        ->method(...
    $Foo
        ->expects($this->next())
        ->method(...
    $Bar
        ->expects($this->next('Bar'))
        ->method(...
    $Bar
        ->expects($this->next('Bar'))
        ->method(...
    $Foo
        ->expects($this->next())
        ->method(...
Adds composerability for the CounterHelperTrait.
Adds docblocks to CounterHelperTraitTest.
Changes array() to [].
Adds CounterHelperTrait to the README.
Makes the traits clickable in the README.
Merge pull request #4 from Phally/counter-helper

CounterHelperTrait