proofreading README

* considering is a frenchism in this context
* fix consistency in the use of you / we

Change-Id: I15af29d075fba36ed155e9fac2b178b7fc4e810a
Signed-off-by: Loic Dachary <loic@dachary.org>
Signed-off-by: Sahid Orentino Ferdjaoui <sahid.ferdjaoui@cloudwatt.com>