Implemented if statements and made putuint work with 0

flagpole/fvmstd.fp

@@ -8,16 +8,19 @@ endproc
 
 proc putuint
   @val
+  if &val 0 == then
+    48 :putchar return
+  endif
   1 @divisor
-
+  
   while &val &divisor u/ 9 u> do
     10 &divisor u* @divisor
   endwhile
-
+  
   while &divisor 0 u> do
     &val &divisor u/ 10 u%
     48 u+ :putchar
-
+  
     &divisor 10 u/ @divisor
   endwhile
 endproc