Script tests re-added, all tests can run under gdb

Also fixed a minor bug with printing, and removed the ability to
configure the parser.

Added and updated QUICKSTART.md as a quick way to get people started.

There's some broken scripts under 'scripts/' that require functions to
work properly.

tests/scripts/test_variables.toy

@@ -0,0 +1,160 @@
+//declare a variable with an initial value
+var answer = 42;
+
+//declare a variable without an initial value
+var empty;
+
+//assign a previously existing variable
+answer = 6 * 9;
+
+//access a variable
+answer = answer + 1;
+
+//compound assignments
+answer += 5;
+answer -= 5;
+answer *= 9;
+answer /= 2;
+answer %= 10;
+
+//equality checks
+print 1 == 1; //true
+print 1 != 1; //false
+
+//comparison checks
+print 1 < 2; //true
+
+print "foo" > "bar"; //true
+
+print 1 < 2; //true
+print 1 > 2; //false
+
+print 2 <= 2; //true
+print 2 >= 2; //true
+
+print 1 <= 2; //true
+print 1 >= 2; //false
+
+//logical checks
+print true && true; //true
+print true && false; //false
+print false && true; //false
+print false && false; //false
+
+print true || true; //true
+print true || false; //true
+print false || true; //true
+print false || false; //false
+
+print !true; //false
+print !false; //true
+
+//logical AND short-circuits and chained assignments
+{
+	var a = 1;
+	var b = 2;
+	var c = a + 1 && b + 2;
+
+	assert a == 1, "short circuit 1.1";
+	assert b == 2, "short circuit 1.2";
+	assert c == 4, "short circuit 1.3";
+}
+
+{
+	var a = 1;
+	var b = 2;
+	var c = a = (a + 1) && b + 2;
+
+	assert a == 4, "short circuit 2.1";
+	assert b == 2, "short circuit 2.2";
+	assert c == 4, "short circuit 2.3";
+}
+
+{
+	var a = 1;
+	var b = 2;
+	var c = a = a + 1 && b + 2;
+
+	assert a == 4, "short circuit 3.1";
+	assert b == 2, "short circuit 3.2";
+	assert c == 4, "short circuit 3.3";
+}
+
+//logical OR short-circuits and chained assignments
+{
+	var a = 1;
+	var b = 2;
+	var c = a + 1 || b + 2;
+
+	assert a == 1, "short circuit 4.1";
+	assert b == 2, "short circuit 4.2";
+	assert c == 2, "short circuit 4.3";
+}
+
+{
+	var a = 1;
+	var b = 2;
+	var c = a = (a + 1) || b + 2;
+
+	assert a == 2, "short circuit 5.1";
+	assert b == 2, "short circuit 5.2";
+	assert c == 2, "short circuit 5.3";
+}
+
+{
+	var a = 1;
+	var b = 2;
+	var c = a = a + 1 || b + 2;
+
+	assert a == 2, "short circuit 6.1";
+	assert b == 2, "short circuit 6.2";
+	assert c == 2, "short circuit 6.3";
+}
+
+//types
+{
+	var a: int;
+	var b: int = 42;
+
+	a = 69;
+	b = 8891;
+
+	print a;
+	print b;
+}
+
+//constants
+{
+	var c: int const = 42;
+	print c;
+}
+
+//indexing
+{
+	var s = "Hello" .. "world!";
+	print s[3, 3];
+}
+
+//increment & decrement (prefix)
+{
+	var a = 42;
+	assert a == 42, "prefix increment & decrement 1.1";
+	assert ++a == 43, "prefix increment & decrement 1.2";
+	assert a == 43, "prefix increment & decrement 1.3";
+	assert --a == 42, "prefix increment & decrement 1.4";
+	assert a == 42, "prefix increment & decrement 1.5";
+}
+
+//increment & decrement (postfix)
+{
+	var a = 42;
+	assert a == 42, "postfix increment & decrement 1.1";
+	assert a++ == 42, "postfix increment & decrement 1.2";
+	assert a == 43, "postfix increment & decrement 1.3";
+	assert a-- == 43, "postfix increment & decrement 1.4";
+	assert a == 42, "postfix increment & decrement 1.5";
+
+	print a;
+}
+
+//TODO: type casting