0.0.4-alpha.3-->beta.1: 

* Add forgotten __version__ in `fuefit` module.
* Imprint fuefit-version in Excel.
FIX Excel tests not to use ExcelRunner file.
RENAME model-->datamodel

* docs, test: DOCTEST README
* docs: Improve Python-usage section.
* model: Validation does not return back the model.
* model: Remove unused fuel_curve code.
excel: TEST ExcelRunner when run from python.

* Backtrack ver 0.0.4-beta.1-->alpha.4
RENAME fuefit_excel_runner --> FuefitExcelRunner

* Remove and Ignore xlwings tmp files from git.
Enable TravisCI continuous-testing!

* build: FIX setup.cfg renaming `model` in cmds.
* docs: Add TravisCI build-badge.
* docs: Various sphinx fixes for API-ref.
* docs: Updated release CHANGES.