[Find] Improve Find by grouping its widgets inside a QGroupbox

- Fix Find by grouping its widgets inside a QGroupbox.
- Fix Replace by grouping its widgets inside a QGroupbox.
- Update translations.
- PEP8 / Lint compliant.

![temp](https://f.cloud.github.com/assets/1189414/2372202/e0a2d1be-a836-11e3-8afd-fa61f551f54e.jpg)

The idea behind its to make more clear visually, ala 
*" What im closing with 2 Close buttons togheter?; Whats the Forward/Backward buttons for? "*

Brancho: fix/find :rabbit2: