Translated Pixel Dungeon

Changes were made to translate the game.
**NOTE: This pull request will only be applied after https://github.com/watabou/PD-classes/pull/1**

**Changes:**
1. Removal of strings throughout the source code;
2. Creation of Strings of all source code in the file ```res/values/strings.xml```. The tags of each string will have to name ```<Class Name>_<String Name>```.
3. Translation of all strings for Brazilian Portuguese
4. Validation of all texts in the game in English(keep as current) and Portuguese(adjust syntax).
5. Some improvements in the use of common variables
6. The merge was done with version 1.7.2
7. Validation, validation and more validations.