Define a default value for configfile

issue4164
review7571002
Add image widget to rn[gc]

issue3729
review3991003
Log error if timezone is not UTC

issue4192
review6521004
RawConfigParser.getboolean raise AttributeError in case of missing option

--HG--
extra : rebase_source : 99ce7c75b6b79782b99ac25f20f0db101491d2ec