Compatibility with CDH4.1
Merge update from edwardcapriolo
Cloudera version bump to 4.2.1 and log4j bump to 1.2.17 (fixes some annoying maven dependency issues)
Add option to ignore files by regex
Add public Cloudera CDH4 repository.
Add gitingore file.
Update SortingFileSystem test fixture to work with PathFilter.

8e226c7f3c5102594ab83a5523c2cb8fde6d47d9 introduced the need to filter a path.
Since the test fixture is order dependent, it was broken until this change.
Use updated Hadoop property, 'dfs.blocksize', throughout tests.
Replace deprecated 'fs.default.name' property with 'fs.defaultFS' throughout tests.
Acquiesce Maven warnings.