Prepare README and ReleaseNotes for 4.5.4

Just so I don't forget. Still some more testing needed.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

README

@@ -1,4 +1,4 @@
-This is the README file for Subsurface 4.5.3
+This is the README file for Subsurface 4.5.4
 
 Please check the ReleaseNotes.txt for details about new features and
 changes since Subsurface 4.5 (and earlier versions).
@@ -24,11 +24,11 @@ If you want the latest release (instead of the bleeding edge
 development version) you can either get this via git or the release tar
 ball. After cloning run the following command:
 
-git checkout v4.5.3  (or whatever the last release is)
+git checkout v4.5.4  (or whatever the last release is)
 
 or download a tar ball from:
 
-http://subsurface-divelog.org/downloads/Subsurface-4.5.3.tgz
+http://subsurface-divelog.org/downloads/Subsurface-4.5.4.tgz
 
 Detailed build instructions can be found in the INSTALL file.
 

ReleaseNotes/ReleaseNotes.txt

@@ -1,8 +1,22 @@
-// _Subsurface_ 4.5.3 Release Notes
+// _Subsurface_ 4.5.4 Release Notes
 
-_Subsurface_ 4.5.3 - October 2015
+_Subsurface_ 4.5.4 - March 2016
 ---------------------------------
 
+Some of the changes since _Subsurface_ 4.5.3
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- Update to latest libdivecomputer to fix a number of issues in the
+  parsing of dive computer data (Shearmos Amphos Air, Shearwater Predator,
+  several Oceanic models)
+- Add support for Oceanic / Aeris F11, DiveSystem iX3M, Shearwater Perdix
+- Fix several issues with imports from CSV, divelogs.de and other sources
+- Add better support for OSTC3 configuration
+- Fix potential rounding error when exporting weight systems
+- Add statistics by dive type
+- Small UI fixes
+
+
 Some of the changes since _Subsurface_ 4.5.2
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~