new release display and information

This patch changes the way to display the release information.
Also update the release name to Louis Riel - beta2

Now the revision is replaced by the build date.

This value is generated as following pseudo-code:

if SOURCE_DATE_EPOCH is set
  it's value must be a number of seconds since epoch.
  it's used to generate the final build date displayed.
else if RING_CLIENT_BUILD_DATE is set
  it's value is used as-it as the final build date displayed.
else
  the current date of the system is used to generate the final build date displayed.

Reviewed-by: Alexandre Viau <alexandre.viau@savoirfairelinux.com>
Change-Id: Ifa431b8fa4f8945cf9a25fef028712ad0e40a0f3
diff --git a/src/revision.h.in b/src/revision.h.in
index 071578e..6db09dd 100644
--- a/src/revision.h.in
+++ b/src/revision.h.in
@@ -1,3 +1,4 @@
 /* cmake will generate revision.h with a define containing the git revision (if found) */
 
 #define RING_CLIENT_REVISION "@RING_CLIENT_REVISION@"
+#define RING_CLIENT_BUILD_DATE "@RING_CLIENT_BUILD_DATE@"