Fix a typo
Merge pull request #7 from seratch/patch-1

Fix a typo in README
Android 19 on a 4.4.2 simulator seems to return a null when getHeaderFields is called on a headerless request instead of an empty map which results in an NPE.
I forgot this was Java.
Merge pull request #8 from andrepew/master

When an Android app doesn't have the INTERNET permission, getHeaderFields() returns null resulting in NPE
fix #4 gracefully shutdown all ExecutorServices
Merge branch 'master' of github.com:nkzawa/engine.io-client.java
increase timeout
add try-finally
synchronize access to the ExecutorService
improve test server
fix tests
Release 0.2.3