Basic instrumentation for function replacement
Refactored text marking code from HTMLInstrumentation. Made unit tests not depend on actual function template.
Basic function replacement limping along. Won't work for more than one JS file.
Function addition is limping along. Only seems to work properly if you assign functions to a var as well as giving them a name, and there's a funny 'lag' where it doesn't seem to take the first time you run an updated function in some cases.
Added TODO for cases that don't work
Added TODO
Added BUG info about function decl hoisting