Resolve source linting issues

Also:

* Replaces inline md5 with a module dependency
* Removes atob/btoa polyfill that was inlined
Resolve test linting issues
Lint code before tests on travis
Run linting before tests with npm test
Fix bad UMD bundle issues
Release v0.2.9
Don't use the UMD build as the main for Node

Closes #19
Fix example of using proxyquire to override firebase

Re #19
Merge branch 'browser-build'

* browser-build:
  Fix example of using proxyquire to override firebase
  Don't use the UMD build as the main for Node
Release v0.3.0
basic implementation of auth
feedback from @katowulf and @bendrucker
return object for auth for consistency - thanks @katowulf
Merge pull request #20 from mattvv/master

basic implementation of auth
Fix link to AngularFire unit tests

Closes #21
Add note about not editing browser build

Ref #23
Fix "bad child path" exception after using leading/trailing slashes in calls to #child
test: leading and trailing slashes in #child paths

Ref #23
Merge pull request #23 from gajuro/master

test: leading and trailing slashes in #child paths
Fix "bad child path" exception after using leading/trailing slashes in calls to #child

Closes #23
once should not throw away cancel function