Examples cleanup
Compatibility with python 2.6.

 * tarfile module in python2.6 has not own context manager.
Refactoring over upload application tool.

 * functional decomposition done
 * usage updated
Duplicate logging has been fixed
Git downloader can now redirect its output stream to the specified stream
Code cleanup
PythonModuleInstaller has been improved

 * errors now is thrown when input and output paths not exist. Also exception is raised when virtual environment already exists.
 * some magic consts have been replaced
 * install and download progress can now be shown in specified stream
 * also code cleanup done
Magic strings refactoring
ConcurrentWorker argument processing fixed

 * if concurrent worker is created via decorator, function first argument can be mistakenly interpreted as `ioLoop`. Now it fixed
Subprocess output can now be redirected to the StreamHandler
Local Upload tool can now create virtual environment for python
Information message added for application upload tool with building virtual environment
Merge branch 'master' of github.com:cocaine/cocaine-framework-python