Feature/travis ci cache third party

Add BufferArg as the Function argument type and modify the Function prototype to remove the inouts argument.

Add some functions to PaddleAPI.h

Add THIRD_PARTY_PATH

Disable dynamic linked cuda libs default

Check Python if system already equipped one

Traffic demo branch

Find swig in system first

Download, build, install External dependencies via cmake

add paddle_test_util static lib to simplify unit test.

remove double spaces, remove chinese character "，"

Move Execepts into arch/osx dir