samples: add Terra samples

source: https://github.com/zdevito/terra/tree/master/tests

samples/Terra/debugcallback.t

@@ -0,0 +1,23 @@
+
+terralib.settypeerrordebugcallback(function(o)
+    o:printpretty()
+end)
+
+
+local function dosomecomplicatedstuff(a)
+    return `@a
+end
+
+local s,e = pcall(function()
+
+    local terra what(a : &opaque)
+        var b = [dosomecomplicatedstuff(a)]
+        return b
+    end
+    what:compile()
+
+end)
+
+assert(not s)
+print(e)
+assert(e:match("Errors reported during"))