LoggingHandler inefficient

[oli-h]

When using the RequestLog feature, then for every request passing through a Gateleen server a new Instance of class org.swisspush.gateleen.logging.LoggingHandler is instanciated.
The constructor of this class does a lot of stuff over and over again which could be done 'just once' (or only once when the logging configuration changes).
Examples:

• Iterate over the entries of each LoggingFilter and move the "url" key to the head of a list
• LoggingFilters are kept only in a HashMap. Accessing entries in a HashMap is more expensive than it would be with a concrete object
• There are a few "equalsIgnoreCase" String comparisons which is expensive in Java
• All RegExps in the LoggingFilters are compiled (java.util.regex.Pattern.compile(...)) over and over again