Fix unit test error: File exists: '/root/.cache/paddle/dataset'

FIX: Add boost inc dir

Add WITH_GOLANG to control the link of go lib

Allow printer layer to print user-provided message

Move paddle/majel/* to paddle/{platform,framework/*

For example:
layer.printer(input=[x, y], format="x=%s y=%s")

Fix some compile error.

merge with lasted develop branch. Optimizer lib2

Repeat layer for column vector

RecurrentGroup with mixed input sequence types

Add convolution Function

Implement master client for reading training tasks

Add documentation for installing Go when building Paddle manually