[Library] Add code coverage classes.

Squashed commit of the following:

commit 75b98278f31bfe8f6052d64d7355f80bb1595583
Author: Lars Dietrich <lars@dietrich-hosting.de>
Date:   Sat Dec 7 21:47:19 2013 +0100

    [Library] Correct coverage class doc blocks.

commit 606e57601051f6920f9d56beab75d0326e2e6d8e
Author: Lars Dietrich <lars@dietrich-hosting.de>
Date:   Sat Dec 7 21:08:38 2013 +0100

    [doc] Update readme.

commit 9108b2107ba082b8882b3134f24501e908cae58c
Author: Lars Dietrich <lars@dietrich-hosting.de>
Date:   Sat Dec 7 02:41:59 2013 +0100

    [Library] Correct coverage class
    [Test] Add code coverage to test

commit eae3d292c0d2943717abb4bc5152ae59036758ce
Author: Lars Dietrich <lars@dietrich-hosting.de>
Date:   Wed Dec 4 21:47:52 2013 +0100

    [Library] Cleanup coverage class.

commit a05f460e11a52ed63bd5bd5e93fdf9189a030550
Author: Lars Dietrich <lars@dietrich-hosting.de>
Date:   Tue Dec 3 01:25:48 2013 +0100

    [Library] Add coverage class writer.

commit 838d8d83cf55068457de2e010e4e92f4039d9720
Author: Lars Dietrich <lars@dietrich-hosting.de>
Date:   Sat Nov 30 21:20:26 2013 +0100

    [core] Add coverage class.