[6858] Updated Readme about howto build
[6858] Updated Readme about howto build

sazgin/elexis-3-core,sazgin/elexis-3-core,sazgin/elexis-3-core,elexis/elexis-3-core,sazgin/elexis-3-core,elexis/elexis-3-core,elexis/elexis-3-core,elexis/elexis-3-core