glob list instead of simple hdfs list and pattern support for input

Right now hraven accepts a simple hdfs path as input folder and will fetch all job history + conf files underneath it. This pull request adds support for specifying a pattern with wildcards (*) and using hdfs api's globStatus method to list files instead of hraven's recursive listFiles method. This way one can easily shard hraven's job to different years/months/days.
So you are saying that we should no longer support the original format, and everybody _must_ use this new format ? We won't support the older format anymore ?