redmine #215: Added readme file
Issue #2: storage base class and mongodb storage class.
Issue #2: implemented basic player
Issue #2: command-line interface with following commands: list, add, info, rate, remove, play.
Issue #2: Display MIME type in the list and mark clips if file doesn't exist
Issue #3: Code style fixes according pylint in cli module
Issue #2: Fixed StorageError exception handling
Issue #2: add-bunch CLI command.
Issue #2: remove-all-corrupcted CLI command.
Issue #4: Merge master branch to local branch