added missing lines at ends of files
Added argument checking to add, change. remove methods; some renaming.
Small reorganization of code, so that it is more readable.
Merge pull request #1 from hleumas/test

Test
Using unauthenticated acces to mongo database; added comments
Fix package dependencies. Never depend on path.
Replacing group of line comments by a block comment.
Merge pull request #2 from cleandart/test-web-example

Test web example
Merge branch 'master' into cleaning-up

Conflicts:
	bin/example_server.dart
	pubspec.yaml