Activate Travis build and fix scripts to comply with flake8 standards

This PR,
- adds a .travis.yml file at the top-level of the repository and runs flake8
- fix individual scripts to comply with flake8 standards


- [ ] omero/analysis_scripts/Kymograph.py
- [ ] omero/analysis_scripts/Kymograph_Analysis.py
- [ ] omero/analysis_scripts/Plot_Profile.py
- [ ] omero/export_scripts/Batch_Image_Export.py
- [ ] omero/export_scripts/Make_Movie.py
- [ ] omero/figure_scripts/Movie_Figure.py
- [ ] omero/figure_scripts/Movie_ROI_Figure.py
- [ ] omero/figure_scripts/ROI_Split_Figure.py
- [ ] omero/figure_scripts/Split_View_Figure.py
- [ ] omero/figure_scripts/Thumbnail_Figure.py
- [ ] omero/import_scripts/Populate_ROI.py
- [ ] omero/setup_scripts/FLIM_initialise.py
- [ ] omero/util_scripts/Channel_Offsets.py
- [ ] omero/util_scripts/Combine_Images.py
- [ ] omero/util_scripts/Dataset_To_Plate.py
- [ ] omero/util_scripts/Images_From_ROIs.py