Updated gulp and fixed issue #205
Updating files and updating version to 1.5.1
Minor Improvements

- Corrected missing css code and path #206
- Improved buildOptions performance
- Improved behaviour of options with empty label or value
- New select to test when all options being disabled #207
- Removed dead code #205
Merge pull request #208 from acemir/develop

Minor Improvements
Merge pull request #206 from Robdel12/version-1.5.1

Version 1.5.1