cocos: no such command

[TamaMcGlinn]

• cocos2d-x version: latest v4 commit, a8de1cc
• devices test on: debian 9 Jessie
• developing environments
  • NDK version: 21.3.6528147
  • Xcode version: n/a
  • VS version: n/a
  • browser type and version: n/a

Steps to Reproduce:

1. Clone the repository
2. Follow all the readme steps for linux
   1. python download-deps.py
   2. git submodule update --init
   3. ./setup.py
   4. source ~/.bashrc
   5. ./install-linux-deps.sh
3. Attempt 'Running tests', which requires the 'cocos' binary to be available, which it isn't because it hasn't been built yet.

I am assuming the step missing in the readme is to do mkdir build && cd build && cmake .. && make but this isn't obvious and should be in the README.

[TamaMcGlinn]

I've made a pullrequest to add this to the readme, since it now seems to be working.