Fixed the library imports for tests on Windows platform

The `SD_SRC` directory a cygwin path and so not compatible with the
Windows Python executable.

To support running tests on Windows plaform through make.

   $ make test PYTHON=<python executable>

We need an alternative way to add the `SD_SRC` directory into the
Python system path. So we need to change the current working
directory to `SD_SRC`.
Fixed open_tarfile cleanup on Windows platform

On Windows platform the tar file is not delete on close because
it need to be close before removing the file (resource used).
Added the config file for appveyor.com continuous integration
Fixed setup directory location for tests
Merge pull request #38 from alquerci/add/ci/appveyor

[WIP] Added the config file for appveyor.com continuous integration
Merge pull request #35 from alquerci/fix/win_open_tarfile_cleanup

Fixed open_tarfile cleanup on Windows platform
Merge pull request #36 from alquerci/fix/test/win_imports

Fixed the library imports for tests on Windows platform
Merge pull request #39 from alquerci/fix/test/setup_dir

Fixed setup directory location for tests
Moved user config file detection to a dedicated method
Use the program usage of the argparse Python module on a parse error
Moved the `CygAptSetup` instantiation after argv parsing
`parse_rc` now parse all configuration
Clarified the steps on `CygAptMain.main` method