Update index.js

Added support for type `requirejs`
This will add optional 4th option to generated script tag as an attribute.
For JS block type:
Any attributes which come after the file name will be added to resulting script tag
For JS block type:
Any attributes which come after the file name will be added to resulting script tag

Added  ?: to regex
Merge pull request #13 from xmlking/master

Added support for type `requirejs`
Versiom bump
Removed `jsasync` type
Version bump
Updated docs
minor fix to output correct link tag without trailing slash
Merge pull request #15 from fisch0920/master

[bug] CSS link tag trailing slash
0.3.1