Upate README and CONTRIBUTING files

* README.md: Fix links, update tagline, small fixes

* CONTRIBUTING.md: Update links, make it read better

* index.html: update links, make it read better

Don't know how this factors into issue#459

* CONTRIBUTING.md: remove errant bracket

create a cli with python.
python will be installed by default on a lot of system.

 * use getpass python native module
   Fixes: https://github.com/lesspass/lesspass/issues/305

 * use lesspass python code generator from Maurits van der Schee
   Fixes: https://github.com/lesspass/lesspass/issues/328

tested with python2.7 and python3.6

breaking changes:

 * -c is associated with --copy flag to copy the password
 * -C is associated with the counter (previously -c)

In order to be able to continue the development I need to clean the workspace.
lesspass-move, lesspass-snap and lesspass-cozy are removed.
lesspass-mobile will replace lesspass-cordova with a new react native implementation.
lesspass-core is now splited into specific repo (entropy, fingerprint and render-password)
The workspace use lerna now to manage the mono repo more efficiently.
lesspass-profiles is a new container available only in a pro version.

merci Stéphane 👍

see https://github.com/lesspass/cli/pull/7

... to include link to the German blog entry.

fixes https://github.com/lesspass/lesspass/issues/14