some docs for devs, added a few examples, implemented syscalls

examples/hello_world.mcl

@@ -0,0 +1,18 @@
+
+mem dup 72 @8
+1 + dup 101 @8
+1 + dup 110 @8
+1 + dup 108 @8
+1 + dup 111 @8
+1 + dup 32 @8
+1 + dup 119 @8
+1 + dup 111 @8
+1 + dup 114 @8
+1 + dup 108 @8
+1 + dup 100 @8
+1 + dup 33 @8
+1 + dup 10 @8
+1 +
+
+mem - mem 1 1 syscall3
+

examples/rule110.mcl

@@ -0,0 +1 @@
+// TODO: Make this

examples/seq_100.mcl

@@ -0,0 +1,5 @@
+
+0 while dup 100 < do
+    dup print
+    1 +
+end