Filters received post messages and processes only desired ones

Filters received post messages and processes only desired ones

Adds unlisten method

Merge pull request #2 from Sujsun/unlisten-methods

Add unlisten methods

Parses only string type

Parses only string type

Fixes duplicate window message event binding

Fixes duplicate window message event binding

Adds pop up support

v0.0.2

Update README.md

Initial Release

IPost eases the way the page communicates with iframe window or popup window.