Fixes #165 (`mk_fact_excl_pattern` should not be in server config)

The changes in this pull request remove the `mk_fact_excl_pattern` field from the hanlon_server.conf file, replacing the line that used to define this pattern in that file with code that returns the same pattern. This will prevent users from accidentally changing this field in the hanlon_server.conf file, which could cause issues with how the Microkernel operates (the field was only included in the original configuration file so that we could send it to the Microkernel, it's value is of little interest to the end user of Hanlon).  The changes that were made here were, specifically:

* removing the `attr_accessor` for this field and the code that assigned a default value for this field from the `core/config/server.rb` file and replacing it with a method that returns the same value.
* modifying the code in the `core/config/common.rb` class so that the `mk_fact_excl_pattern` key is filtered out of any keys that are returned to the user from these configuration classes (this will effectively remove the key and it's value from the configuration returned by a GET against the `config` endpoint of the RESTful API).
* adding code to that same file that dynamically adds this field to the "Client Configuration" that is sent back to the Microkernel as part of the response to a Microkernel checkin request.
* cleaning up a small but nagging bug in the `config` slice that left the cursor a green color after a `hanlon config` command; by printing the newline character without a color this shouldn't happen anymore.