RD-4: Implemented V_Init(). Also moved some constants to be more in-line with the original source code

src/doomtype/mod.rs

@@ -0,0 +1,10 @@
+const MAXCHAR: i8 = i8::MAX;
+const MAXSHORT: i16 = i16::MAX;
+const MAXINT: i32 = i32::MAX;
+const MAXLONG: i32 = i32::MAX;
+
+// Minimum values
+const MINCHAR: i8 = i8::MIN;
+const MINSHORT: i16 = i16::MIN;
+const MININT: i32 = i32::MIN;
+const MINLONG: i32 = i32::MIN;