Officegenerator

* Now it's not necesary to set selected coord in freezeAndSelect method. Bottom Right cell is selected by default.
* Fixed rewritten and data only conversion with absolute and relative paths.
* Now you can generate data_only files from ods and xlsx files from other ods and xlsx files, mixing them.

* Added horizontal and vertical totals fast method to ODS and XLSX formats

* Added methods 'create_rewritten_ods' and 'create_rewritten_xlsx' to get quickly a document rewriten by libreoffice with calcs added automatically.
* Added method 'create_data_only_xlsx' to get quickly a xlsx file with formulas converted to calculated data.

* Added skip_up and skip_down parameters in ODS_Read and XLSX_Read 'values()' methods to skip rows as necessary.
* Added method 'values_by_range' in XLSX_Read and ODS_Read.
* XLSX_Write and XLSX_Read have a new constructor paramter 'data_only' to show last save values of each cell instead of formulas.

* Huge performance improvement reading ODS files.
* Added skip_down to getColumnValues method and skip_right to getRowValues method.
* Fixed bug getting string cells in ods.

* Added Model and XLSX_Read to module visibility.
* Added Model totals to xlsx and ods files.
* [XLSX] overwrite_formula class type parameter is now a string to avoid innecesary imports.
* Improved formula styles and types (Money, Currency, bool).
* Added Model_Auto method for fast sheets.
* You can now generate a file from a Model method.
* Faster demo generation.
* Added standard sheets demos.