JCR-2113: Writing access control

This patch addresses the following as indicated in https://issues.apache.org/jira/browse/JCR-2113:
a. adjust jcr2dav module and make sure the RepositoryConfig gets a valid ac-provider configuration parameter set
b. complete setPolicy, Batch#setTree, + testing
c. complete removePolicy for jcr2spi and complete implementation for removal of protected items on jcr-server.

really i didn't do this... may be i had too much coffee:) i now see what you mean. i will try to read the file from the app classpath... something like this:

InputStream is = getClass().getClassLoader().getResourceAsStream(ACCESS_CONTROL_PROVIDER_PROPERTIES);

String filePath = // some code here that converts the InputStream to a String

and finally...
parameters.put(ACCESS_CONTROL_PROVIDER_PROPERTIES, filePath