Add more small test programs.

programs/basic_draw_number.chalk

@@ -0,0 +1,3 @@
+fun main(): u0 {
+    draw_number(69, 1, 1);
+}

programs/basic_if.chalk

@@ -0,0 +1,17 @@
+fun main(): u0 {
+    var a = 3+3;
+    if(a) {
+        a = 0;
+    }
+
+    var b = 0;
+    if(b) {
+        b = 4;
+    }
+
+    if(b) {
+        b = 4;
+    } else {
+        b = 5;
+    }
+}

programs/basic_input.chalk

@@ -0,0 +1,4 @@
+fun main(): u0 {
+    var a = get_key();
+    var b = get_key();
+}

programs/basic_while.chalk

@@ -0,0 +1,8 @@
+fun main(): u0 {
+    var a = 5;
+    var b = 0;
+    while(a) {
+        b = b + 2;
+        a = a - 1;
+    }
+}

programs/comb_fib.chalk

@@ -0,0 +1,14 @@
+fun main(): u0 {
+    var a = 1;
+    var b = 1;
+    while(233 - a) {
+        draw_number(a, 24, 13);
+        set_delay(30);
+        var temp = a;
+        a = b;
+        b = b + temp;
+        while(get_delay()){}
+        draw_number(temp, 24, 13);
+    }
+    draw_number(a, 24, 13);
+}

programs/comb_input.chalk

@@ -0,0 +1,13 @@
+fun main(): u0 {
+    var a = 1;
+    var b = 0;
+    var previous = 0;
+    draw_number(0, 24, 13);
+
+    while(a) {
+        previous = b;
+        b = get_key();
+        draw_number(previous, 24, 13);
+        draw_number(b, 24, 13);
+    }
+}