Removed extraneous debug information from assembly output.
Fixed some problems with lexical scope.
Added support for calling procedures.
Added support for if statements to compiler.
Added support for lexically scoped variables to compiler.
Added program for demonstrating constants.
Added comments and minor tweaks to existing programs.
Added demonstration program calculating squares using a procedure.
Added example program demonstrating scope.
Added support for constants.
Fixed minor error with operator names.
Added support for IF statement to interpreter.
Corrected exception instances to useful error classes.
Fixed a bug where stack would not be inspected correctly.
Fix a minor bug parsing IF statements.
Ignore case of keyword tokens.
Added support for comments in PL/1 source code.
Add 3 examples.
Add initial project work.