samples: add Terra samples

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

samples/Terra/exportdynamic.t

@@ -0,0 +1,9 @@
+terralib.includepath = terralib.terrahome.."/include/terra"
+C = terralib.includecstring [[
+    #include "lua.h"
+    #include "lauxlib.h"
+]]
+
+local s = C.luaL_newstate()
+assert(C.lua_gettop(s) == 0)
+