Adds install informations

INSTALL

+How to install memopol
+
+1. Create a directory containing the whole project (say ~memopol)
+2. Create a python virtualenv in ~memopol : ~memopol/ve
+3. Clone memopol main repository (http://git.laquadrature.net/memopol/memopol_political_memory) in ~memopol/memopol_political_memory
+4. Clone django-representative directory (http://git.laquadrature.net/memopol/compotista_django-representatives) in ~memopol/django-representatives
+5. Clone the last version of django-chronograph (https://bitbucket.org/wnielson/django-chronograph) in ~memopol/django-chronograph
+(It seems that the version in pip is not up to date…)
+6. Symlink ~memopol/memopol_political_memory/representatives -> ~memopol/django-representatives/representatives
+7. Symlink ~memopol/memopol_political_memory/chronograph -> ~memopol/django-chronograph/chronograph
+8. Install requierements in the virtualenv with pip install -r ~memopol//memopol_political_memory/requierements
+9. Config your database in ~memopol/memopol_political_memory/settings.py
+10. Sync the database python manage.py syncdb
+11. Import mep from a compotista instance : python manage.py update update_eu_mps
+12. Run the server
+