Fixed - and + as unary operators, negative numbers, etc

tests/test_negative_number_unary.expected_results

@@ -0,0 +1,5 @@
+-1
+1
+-1
+7
+-7

tests/test_negative_number_unary.krak

@@ -0,0 +1,14 @@
+import io:*
+
+|int| main() {
+    |int| a = -1
+    println(a)
+    println(-a)
+    println(+a); // this is still -1! (as C has it, anyway) (darn comment/semicolon interaction)
+
+    |int| b = 7
+    println(b)
+    println(-b)
+
+    return 0;
+}