nodes: Update docstrings and comments
transform: Support basic operator overloading
transform: Support indexing (gets only)
transform: Indexed assignments
checker: Minor refactoring
checker: Continue refactoring
transform: Fix generic operator methods
transform: 'in' operations
Fix code formatting
Export unary expression method types
transform: Add unary operator test case
icode: Start work on operator overloading
icode: Support the 'in' operator
icode: Support indexed get
icode: Support indexed set
icode: Overloaded unary operations
icode: Fix 'in' operator
cgen: Add operator overloading test case
Add transform test cases