aakpat6/spectra — pull request #15 by benjamminf (2014-01-06 08:54:35+00:00)
Title: Add multiply, invert and screen methods

Added the blend modes multiply and screen as well as a method to invert
the color. Test cases provided.

Usage:
```javascript
Spectra(...).multiply(...);
Spectra(...).screen(...);
Spectra(...).invert();
```