issue #35: Issues with Dark LAFs (f.e. Dark Metal)


[ui] updated custom forms/options to be compatible to dark themes
introduced in NB74 (labels use correct colors, tooltips use link color,
all tables use default colors, buttons have size height, ...)
[ui] redesign of optionpanel - resizes correctly now

See the updated UI using Dark Metal and the applied patch. IMHO it looks much cleaner than before.
NEW:
![2013-08-11_00h39_09](https://f.cloud.github.com/assets/1857095/943347/f898646a-020e-11e3-8fd8-ea9fab8da5f2.png)

OLD:
![2013-08-10_12h57_12](https://f.cloud.github.com/assets/1857095/942414/705f5ca0-01ac-11e3-955e-ef2c45566d14.png)

![2013-08-10_12h58_48](https://f.cloud.github.com/assets/1857095/942411/3b5e44bc-01ac-11e3-9b7e-b34eee346abb.png)