Merge pull request #10 from tbenade/master

added url encoding of uri components, added delete method to groups, add...
Update README.md

Added a section about how to contribute.
Added messages.attachments method to fetch messages with attachments
Merge pull request #11 from willeeklund/master

Added messages.attachments method to fetch messages with attachments
Update package.json

Bumped up the version number.
Update README.md

Updated the changelog.
Merge pull request #12 from tbenade/master

added like method to messages api
Upgrade npm before running the build
Wrong npm command
Dropped Node 0.8 since some of the dependencies don't support it
Bumped up the version number and updated the changelog