Remote unnecessary constants
Fix a wrong definition
Remove 'node' option from app env
Updating 'Usage' section
add the leo_rpc:port() function
Update README.md
Update README.md
Add sentences
Merge pull request #2 from egisatoshi/develop

Remove 'node' option from app env
Bump leo_pod to 0.6.0
Modify getting a worker because of updated leo_pod
Modify for v0.8.2
Modify CHANGELOG correctly
Bump leo_rpc to 0.8.3
Merge branch 'release/0.8.3'