fix ceil transnmission. Previous commit adds : coverage.ini : add comments  + add zgrid option to determine the height of evalu taion coverage.py : now support ceil/floor transmissionsif AP are placed outside of th e structure
fix ceil transnmission. Previous commit adds :
coverage.ini : add comments  + add zgrid option to determine the height of evalu
taion
coverage.py : now support ceil/floor transmissionsif AP are placed outside of th
e structure

pylayers/pylayers,pylayers/pylayers,dialounke/pylayers,dialounke/pylayers