Bug Fix: towards and distance

both towards and distance should optionally take a turtle as a parameter rather than two numbers.
trailing whitespace removed
Add a NotImplementedException

To improve the error reporting, I created a NotImplementedException.  Now super() throws this exception rather than giving a rather unintelligible Name error about super_$rw$ not found.  This should be expanded to all of the builtin functions that are not yet implemented in skulpt.
Bug Fix: Exceptions

The builtin exceptions were not available for users the throw in their Python code.  export them in builtindict.js
All code merged
Changed files for true number types
move t999.py out of test/run
Bug Fix:

turtle.distance(otherturtle) was always returning 0
Update:

When opening a file.  If the file is mapped to a regular html element then use textContent to get the content.  If the file is mapped to a textarea use value so that changed / pasted values are retrieved rather than the initial default values.
Merge branch 'num_types' of github.com:blacatena/skulpt into blacatena-num_types
Expanded math library, set types as per spec
Fix missing bracket in turtle
Merge branch 'num_types' of github.com:blacatena/skulpt into blacatena-num_types
remove some of the forced results, now that Bob's numbers better match real python.
Modify test to only run the runtime tests by default.
fix outf so it does not eat < or >
Change type.js to have a richcompare for type comparisons
Fix type.js  closure compiler gag
Merge branch 'num_types' of github.com:blacatena/skulpt into blacatena-num_types
force t276 to have matching object types.