Small changes to ReleaseNotes format

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

ReleaseNotes/Makefile

@@ -31,7 +31,7 @@ $(OUT)%.pdf: %.txt
 
 $(OUT)%.html: %.txt
 	@echo "if asciidoc isn't found the html file included in the sources is copied"
-	$(ASCIIDOC) -a toc -a toclevels=3 -a themedir=$(PWD) -a theme=$(THEME) -a stylesdir=$(PWD) \
+	$(ASCIIDOC) -a themedir=$(PWD) -a theme=$(THEME) -a stylesdir=$(PWD) \
 		-o $@ $< || cp $(<:%.txt=%.html.git) $@
 
 # Alternatively::

ReleaseNotes/ReleaseNotes.txt

@@ -1,13 +1,10 @@
-Please add release notes on top of the file /CHANGELOG.md
+//Please add release notes on top of the file /CHANGELOG.md
 
-// _Subsurface_ 4.7.5 Release Notes
-
-_Subsurface_ 4.7.6 - Month dd, 2017
-------------------------------------------
+= _Subsurface_ Release Notes
 
 
-_Subsurface_ 4.7.5:
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+New in _Subsurface_ 4.7.5
+~~~~~~~~~~~~~~~~~~~~~~~~~
 
 - Subsurface-mobile: Add button to rescan for BT devices
 - Subsurface-mobile: Enable BLE and GPS on iOS
@@ -40,6 +37,13 @@ _Subsurface_ 4.7.5:
 - Various small improvements in the dive photo UI
 
 
+NOTE: As of _Subsurface_ 4.7.5 we changed the format of this file so that
+the new features are listed under a heading with the release number where
+they were added. Prior to that we always listed the changes since the last
+release, so the changes since _Subsurface_ 4.7.2 below actually are the
+changes that first were released in _Subsurface_ 4.7.4 (as we skipped
+4.7.3).
+
 Some of the changes since _Subsurface_ 4.7.2
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
@@ -465,7 +469,6 @@ operations can now been un-done and subsequently re-done.
 - Don't zoom out the globe to "sky view" when a dive site has no GPS data
 - Various other small fixes
 
-
 Some of the changes since _Subsurface_ 4.4.1
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~