Initial ideas about the REST server

See #6
More comments for design brain storm
Add basic structure to manage HTTP requests
New script to generate test cover reports
Add tests to improve test covering
100% unit test covering
REST server domain get implemented
Refactory in REST server MUX
Check content related fields in HTTP header
Small dummy comment fix (OCD?)
Protocol that will be used in the REST interface
Initial structures for transcoding request protocol objects to model objects
Conversion from DS request object to DS model object
Reorganize packages and add some tests for protocol layer
More conversions and tests between protocol <-> model
Checking domain name syntax
Add support to DNSKEY in protocol (that will be converted into DS records)
Change functions orders
Check Date HTTP header field for reply attacks
Check If-Match HTTP header in PUT action