Modify the arguments description of ConvFunctionBase. And add the definition of backward input and backward filter function.

* Fix #1877

* Also test std::vector
* Use std::vector to PadConf

* CHECK_XX in glog need the left and right values are both signed or
  unsigned integer. So we could use integer literal syntax in C/C++
  to make literal unsigned or signed. Add suffix 'UL' means unsigned
  long.