NLeSC/Xenon: First beta release of Xenon 1.2.0

This is a beta release of version 1.1.0 of Xenon. Notable changes compared to v1.1.0: added WeDAV adaptor. added OSX testing in Travis Bugfixes: many small bugfixes fixed a Windows delete directory quirk fixed Windows homedir expansion cleanly close directory streams in several test (Windows will not delete a directory if there are streams open). What's missing: There is no adaptor writing documentation at the moment, nor is the Javadoc complete for the internals methods of the adaptor implementations. It should be made easier to inspect at runtime which adaptors are available and what properties they support. We can always use more adaptors, e.g, for S3, SWIFT, HDFS, YARN, Azure-Batch, etc. These are planned for 1.3 or later. We can always use more interfaces, e.g. for clouds. This is planned for 2.0