generic changes, process refactoring, `rotate` implementation and tests.
readme updated.
according to PR comment - fixed imports
- multi-line imports now uses `()` instead of `\`.
- fixed import groups by pep8.
- imports are sorted alphabetically.
according to PR comment - message for ArgumentsError is now more explanatory.
according to PR comment - removed unnecessary inline comment.
according to PR comment - operations on Image manipulates the internal stream + test.
removed unnecessary `asynchronous` decorator.
Merge pull request #6 from dotpot/fix-remove-unnecessary-decorator

removed unnecessary `asynchronous` decorator.
Merge branch 'feat-implement-rotate-functionality' of https://github.com/dotpot/pilbox into dotpot-feat-implement-rotate-functionality

Conflicts:
	pilbox/app.py
Minor formatting changes
Resolved pep8 issues
More minor formatting changes
Integrated rotate pull request, added multi-operation support
Updated README: fixed calling headers
Added a sub-region selection operation
Added negative out-of-bounds check for region rectangles
Added region selection from the command-line, minor README changes
Added Pilbox as a PyPI package
Update README changes for PyPI package
Added unittest2 install for python 2.6