* bugfix: env exists check error
* support to avoid re-build pyarrow in project
* bugfix: adapt gtest for centos lib64
* bugfix: check gtest lib exists in the directory
* bugfix: find gtest with checking all libs exists
* prefix RAY_ to thirdparty env variables to avoid conflicts with other module
* arrow use glog from ray
* change the glog and gtest install dir
* enable using thirdparty env variable to find installed dependency, to speed up the build process
* fix target dependency in cmake. :-) too chaos in each CMakeLists
* check env variable defined directory exists
* use cmake to build ray project, no need to appply build.sh before cmake, fix some abuse of cmake, improve the build performance
* support boost external project, avoid using the system or build.sh boost
* keep compatible with build.sh, remove boost and arrow build from it.
* bugfix: parquet bison version control, plasma_java lib install problem
* bugfix: cmake, do not compile plasma java client if no need
* bugfix: component failures test timeout machenism has problem for plasma manager failed case
* bugfix: arrow use lib64 in centos, travis check-git-clang-format-output.sh does not support other branches except master
* revert some fix
* set arrow python executable, fix format error in component_failures_test.py
* make clean arrow python build directory
* update cmake code style, back to support cmake minimum version 3.4
