Merge pull request #33 from missing/master

Fix for unneeded extra tab that opens on Firefox.
Clarified filename saving capabilities
Added filename support for Firefox and Opera Next
Almost forgot IE supports it as well
Might as well make it very clear that the other browsers *do not* support filenames
Removing old FAQ that doesn't apply to current gen browsers that all support filenames now
Increased bottom margin in the demo
More padding/margin fixes
Update README.md
Add feature detection code snippet; closes #27
Merge pull request #34 from mondalaci/master

Add feature detection code snippet
Update README.md
Update README.md
Started rewriting README

The goal is to begin making this more understandable for people
confused about what FileSaver is and how it can work across all
browsers.