* Get rid of the dependency of Go compiler when WITH_GOLANG is OFF.

* Minor modification to the documentation.

* Remove the downloading and installing of Go compiler when build developing Docker image for android.

* Minor modifcation to the documentation's format.

* Change the default value of WITH_GOLANG to OFF in paddle/scripts/docker/build.sh.

* Add English version of Android cross-compiling document

* Add English version of Android cross-compiling document

* Follow comments from Yi-qun and Kavya