Simplify code
Simplify writing to update.json.
Merge pull request #122 from gmist/with_open_file

Simplify writing to update.json
Added checking requirements.
Unification checking of Internet connection.
Removed checking of the pip/virtualenv.
Do not show help link for test of Internet connection.
Parameter _external in url_for in Task.py

Instead of manually concatenating stuff, you can define it as external so it builds the proper url for you.
Merge pull request #124 from topless/patch-5

Parameter _external in url_for in Task.py
Merge pull request #123 from gmist/doctor

Added checking of requirements
Silly refactor
Deleted all 3dr python dependencies (broken commit).
Added support pip (with and without virtualenv).

Added pip.json syntactic sugar.

Refactoring

Supressed pylint warnings.

Added 'pkg_name' option for packages whose 'pip name' does not match with pkg name.

Ignore all global packages from sys.path.

Added *.dist-info to ignore list.

Fix https://github.com/pypa/pip/issues/1439 (added '--no-use-wheel' option).
Now all dependencies are not resolved by default.
Simplify code.
Reformat code.
Rename "install_venv" function.
Refactoring - extracted "create_virtualenv" function.
Simplify code.
Simplify detection of GAE directory.
Fix detection of GAE directory on Windows.