autoscale config better templates
--link option in TODO
more functional headers parsing
added TODO comment
header values in config

The value in headers dict can be a string or a dict. When it is a
string, it is considered as header value, otherwise a dict with "env" is
expected. The env will point to env variable from where the value is to
be taken
configs updated

based on latest headers change and templates change earlier
raxid minor help changed
uriprefix need not be from env

it can given directly in the config. If it has to be taken from env, the
value should be a dict containing the env property