[DummyLSTM] Add Dummy LSTM custom example

[DummyLSTM] Add Dummy LSTM custom example

Add Dymmy LSTM custom example. Two input stream and two outputstream.
First input is recursion and Second input is new input stream. First
output is recursion stream which is matched with first inputstream and
the second output stream is matched with second input stream.

 - in2_tmp0 = (in2+in1)/2 (in2_tmp0 : mimic sigmoid)
 - in2_tmp1 = tanh(in2)
 - in0 = in0 x in2_tmp0
 - in0 = in0 + (in2_tmp0 x in2_tmp1)
 - out0 = in0
 - out1 = in1 = (tanh(in0) x in2_tmp0)

                     +------------+
         in0 ------->|            |----> out0
         in1 ------->| dummy LSTM |----> out1
         in2 (new)-->|            |  |
                     +------------+  +--> out (equal out1)

**Self evaluation:**
1. Build test:	 [X]Passed [ ]Failed [ ]Skipped
2. Run test:	 [X]Passed [ ]Failed [ ]Skipped

Signed-off-by: jijoong.moon <jijoong.moon@samsung.com>