Reorganise namespaces to have a module containing common code
Some more reorganisations
Modify tests to call new IsValid properly
Don't use filenames (yet)
Add a TODO

Mutable bindings can only be turned into functions by using anonymous
functions
Change message to reflect arguments given
Add a type annotation
Decrease qualification of names
Add AddArgument refactoring

Currently no way of choosing argument name or default value
Implement IsValid for ExtractFunction

Currently only checks if there is an expression at the given range.
Add ExtractFunction to MonoDevelop plugin

As with AddArgument, there is no way to choose the function name.