Prepare release 2.2

CHANGES

+v2.2
+----
 
 - Praxis was really slow on machines where 'localhost' takes seconds
   to resolve, due to some DNS (mis)configuration.  This has been
   observed on Mac OS X "Sierra".
+  Thanks to Patrick Gasser (Singapore-ETH Centre) for reporting the
+  issue, and for his help to diagnose than fix the problem.
 
 v2.1
 ----

src/eu/telecom_bretagne/praxis/common/ReleaseInfo.java

@@ -7,13 +7,13 @@ package eu.telecom_bretagne.praxis.common;
  */
 public abstract class ReleaseInfo
 {
-	public static final String release              = "2.1";
+	public static final String release              = "2.2";
 
 	public static final int    revision             = 0;
 
 	public static final int    application_revision = Configuration.getInt("revision");
 
-	public static final String release_date         = "2017-09-07";
+	public static final String release_date         = "2017-10-18";
 
 	/** The date of the packaging. It has always been the same as {@link #release_date}: use the latter field instead */
 	@Deprecated