Add refactoring: Change signature (append parameter)

[justcla]

Example:

Method already exists: Foo(Bar bar1);

While calling it we decide to add another parameter:
Foo(myBar1, myBar2);

Lightbuld should suggest "Change signature of Foo to add Bar as 2nd parameter"
and result in a new parameter added to the Foo method:
eg. Foo(Bar bar1, Bar bar2);
and updates all other calls to include some default value for the second parameter (or provide a change signature dialog that allows you to specify what the new default value might be).