added validation for loops
using PDA for checking commands
small refactoring
made repeat loops work. added basic error detection. some refactoring on the way
placeholders on the stack at the end are fine
refactoring: simlyfied replacement methods
added conditions
added TODO
added symbols for repeat loops
added missing closing tag
added symbols for conditions
basic map
made map of fixed size
introduced robot, did some refactorings
refactored parser so it can set delays between the steps
styling of goal
prevent browser from following button click
introduced goal
introduced speed
refactored map, introduced stones