Fix a TODO in the code

Refactoring
 * Rename class "TOKEN" to "Token"
 * Split large functions into smaller functions.
   When possible, convert unit tests for these smaller functions
 * Use %varid% instead of %var1% or %var2% in pattern matches
 * create a simplify function that converts "void f(x) int x; {" to "void f(int x) {"
 * improve the variable id so class/struct member variables get a variable id

Preprocessor
 * Expand preprocessor macros

CheckMemoryleak
 * Check for more resource leaks
   - Windows API (CreatePen, GetDC, ..)

New checks
 * Check if there are static functions or variables that are unused

Unit testing
 * There are many checks that doesn't have unit tests
 * Fix any of the tests that are marked as TODO
 * Add a unit test for one of the issues in the tracker
 * Each issue that has a unit test should have a comment about it