Use Regex against Facts for setting default hostgroup

This change would allow the use of a regex against any given fact rather that just the hostname of the machine. 

The first match found  as listed in the config would be applied to the machine. As ruby 1.9.x retains the order of a hash read from config, this should be a reliable way of establishing the priority.

Eventually I would like to perhaps do compound comparisons (If factA = regex and FactB = regex), but this seems like a good start.

Open to any and all suggestions!
'host' won't exist here, as it was defined in the calling method and not passed in to this one. You *could* define the method as `group_matches?(fact, host)` and pass it in, but as these are all in the same class, I'd make host a class variable - change line 13 to 
```
@host, result = import_host_and_facts_without_match_hostgroup(hostname, facts, certname, proxy_id)
```
and use @host wherever you current use host