Adding fix for cyclical variable replacement.
Added unit test to test the resolve props code.
Adding fix to props utils for the string utils.
Using the collections StringUtils join.
fix the 10s logout bug
Update azkaban-executor-start.sh

Fixes a couple of typos that stopped script from working:

- looks like AzkabanExecutorServer lives in azkaban.execapp not azkaban.webapp

- Setting env variable, AZKABAN_OPTS, needed quotes around it.
Merge pull request #24 from aishfenton/master

Fixes a couple of typos that stopped startup script for exec service from working:
Merge remote-tracking branch 'upstream/master'