Officegenerator

* Datetime and date cells are now aligned right by default
* Added creationdate, description, and keywords to metadata in ODF class

- Added overwrite_formula method. Now we can define formula number_format

* Solved bug saving with template
* Unified method to freeze and set position

* Now integers in xlsx show thousands separator.
* Cell number format shows currency and decimals in float numbers, correctly

* Project moved from Sourceforge to Github