Merge pull request #340 from hluu/master

Adding velocity-tools EscapeTool to able to escape certain data element to prevent XSS #339
Use customized classloader to load validator's classpath. This prevents the classpath collision between the validators and Azkaban webserver's own classpath.
Clean up the code.
Format the display of the messages generated by Byte-Ray validator plugin.
Remove the customized classloader as the gradle shadow plugin can resolve the classpath collision issue without changing Azkaban code. Undo the changes leaving only the necessary few lines of changes.
Adding comments explaining the usage of Props in XmlValidatorManager.
Merge pull request #341 from Victsm/validator-plugin

Use customized classloader to load validator's classpath. This prevents ...
Make validator JARs hot-deployable, so when upgrading validators, there's no need to restart Azkaban webserver.
add utf-8 encoding to avoid test failed due to japan char in azkaban-common project.
Merge pull request #343 from hy2014/master

add utf-8 encoding to avoid test failed due to japan char in azkaban-com...
Address the review comment regarding a potential NPE.
Merge pull request #342 from Victsm/validator-plugin

Make validator JARs hot-deployable, so when upgrading validators, there'...
XmlValidatorManager should not throw an exception if the validator dir does not exist.
Update XmlValidatorManagerTest to reflect the modifications in XmlValidatorManager.
Merge pull request #345 from Victsm/validator-plugin

XmlValidatorManager should not throw an exception if the validator dir d...
Fix the issue with XmlValidatorManager passing wrong project archive file path to the validators - issue #351
Merge pull request #352 from Victsm/validator-plugin

Fix the issue with XmlValidatorManager passing wrong project archive fil...
Issue 331 : For job with retry - the attempt count doesn't match with log file when inserting into database
Merge pull request #353 from logiclord/master

Issue 331 : For job with retry - the attempt count doesn't match with lo...
Close the URLClassLoader before reloading the resources.