Bug fix: failing tests were running before all was entered and program was run
Rearranged debugger panels so instructions and variables sections are wider, smaller font for instructions
Tweak width of success screen so text doesn't wrap
Rip out CSS that's no longer used
New lesson: arithmetic with input.
New lesson: Spaces and strings
Support array literals.
Bug fix: p method didn't output newline.
Make Variables component stacked over console, not to the left.  Also make it scrollable.  Also variables go from top to bottom, not left to right.
Oops, old comment.
New HeapComponent is like VariablesComponent but shows object_id so aliasing is visible.  Also started aliasing lesson.  Also ValueComponent now shows arrays.
Oops, tests were broken.
Rip out old solution-toggler code.
Bug fix: strings weren't being shown with string formatting.
Bug fix: after exception, output wasn't turned back on, and there was no sub-exception to track what happened.
Interpreter now supports lambdas! (without args)
Convert ProgramTerminated back to the exception it wrapped.
Call public_send instead of send so we get error messages for calling private methods.
Procs now support parameters!
Oops, should be able to call private methods on main (like p) but not on other objects, not vice versa.