Moved license from GNU GPLv2 to v3

More permissive license.
Removed Travis CI

Removed Travis CI for drone.io, which is easier to use with Dart projects.
Updated README.md

Simplified the readme, in favor of the website.
Quick fix on README.md
Renamed 'readAll' method to 'read'

Issue #28
Changed 'readAll' comment

Issue #28
Moved all exceptions public

Issue #29
- All exceptions are now in lib/exceptions/, which is public
- All exceptions are now out of libraries
Test import to correct exception files

Issue #29
Version 0.1.3

- Minor changes to doc comments.
Merge pull request #30 from magnetfruit/master

Wrong branch