Initial commit
Warmup exercise based on example from lecture
Modified duplicate function.

Two times a subexpression will now result in the subexpression being added
together twice.
Added core/bin/.gitignore to track empty directory
Added build helper script
Added Scanner
Added UnitTest module
Added Scanner unit test
Added file to run all unit tests
Added parser classes
Added code to parse expressions, simpleExpressions, terms, and factors
Added code to parse writeInt
Modified unit test error message
Modified definition of Assignment case class
Added assert
Documentation fix
Removed unwanted test/debug lines
Added code to parse if, while, statements and assignments
Changed line endings in Parser.scala
Added code to parse declarations