[runtime] Enable input reshaping

[hyunsik-yoon]

related to #56

Goal:

• Make the following case work:

  #0 = placeholder([2, 2])
  #1 = placeholder([2])
  #2 = add (#0, #1)
  

• calling sequence of nnfw api is
  1. nnfw_apply_tensorinfo(#0, shape=[4,2]) --> this will change the shape of input
  2. nnfw_compile()
  3. nnfw_set_input()
  4. nnfw_run()

[hyunsik-yoon]

basic work seems to be done. closing this issue.