methodcalls should not modify a method body, but it should be recursive to handle a(b())
add method for finding missing exported globals in a module (recursively). also make checkallmodule recursive, and more thorough
WIP: add a way of extracting the implict interfaces defined by an abstract type
Merge pull request #8 from vtjnash/jn/stuff

Various updates from @vtjnash. Adds exported `checkmissingexports` function, and some internal interface-checking stuff.