python: added README.md file for Python bindings.
python: added README.md file for Python bindings.

Added a README.md file which contains information to be displayed on the main Pypi libiio page.

Signed-off-by: Cristi Iacob <d9a5ee38e079268f5921cacbe589f9990ad49a4f@analog.com>

analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio,analogdevicesinc/libiio