add avoscloud android demo.
Merge branch 'master' of github.com:avos/avoscloud-sdk
Merge branch 'master' of https://github.com/trawor/avoscloud-sdk

Conflicts:
	iOS/AVOSCloud.podspec
update sdk target.
change git ignore and add demo files.
add user demo.
add user demo.
add subobject test.
add show source code.
show source code.
Fixed conflicts