Merge pull request #9 from ricardmo/master

Adds sections in the README, partially resolves issue #8
Adds a 'maybe' modifier for all functions
Documentation for 'maybe' modifier
Merge pull request #10 from ricardmo/maybe

Add a 'maybe' modifier for all functions.
Readme tweaks.
Bump versions.
Update minified script.
Update readme.
Rename types => check in unit tests.
First stab at an improved readme.
More readme improvements.
Readme tweak.
Minor code tidy-up.
Update minified script.
Bump versions.
Fix readme examples.
Update readme.
Fix readme license link.
Added isUrl and verifyUrl
added string check, more unit tests for different non-strings