* Removed Readable- and WritableBytes
** Replaced with Readable-/WritableByteChannel
** Methods now integrated in Readable- and WritableFile
** Replaced positioned read/write by method to set the position
* Partial implementation of nio filesystem
* Addded some tests
* Added project for common test dependencies
* Removed default implementation of Folder#delete
** reason: didn't work because empty folders were not deleted and this
cannot be done in the default implementation