Fix bug with user-code wrappers

The problem was that the user code wrapper was not deserialized from the
config using the user-code class loader. Now we jave a custom
ObjectInputStream that uses the user-code class loader to resolve
classes.
Merge pull request #155 from aljoscha/user-code-loader-bugfix

Fix bug with user-code wrappers
Don't create empty splits in BinaryInputFormat#createInputSplits on one input file.
BinaryInputFormat#createInputSplits on one input file test added.
Avoid invalid ranges in BinaryInputFormat#createInputSplits while creating empty splits.
(HDFS doesn't like invalid ranges and returns an empty array in this case)
Update README.md

* new link to mailing list
* fixed #149
* Added dima irc channel
Update project name in maven poms and readme