Allow overriding bump size (MKIT_BUMPSIZE)

If for some reason, user wants to skip a version or two, this will
override version bumping in vbump_* and some checks new and tag
creation in release_*.

src/include/release.sh

@@ -16,9 +16,9 @@ _bump_version() {
     local oldy=${tmpy#*.}
     local new=""
     case $rlevel in
-        x) new="$((oldx+1)).0.0"            ;;
-        y) new="$oldx.$((oldy+1)).0"        ;;
-        z) new="$oldx.$oldy.$((oldz+1))"    ;;
+        x) new="$((oldx+MKIT_BUMPSIZE)).0.0"            ;;
+        y) new="$oldx.$((oldy+MKIT_BUMPSIZE)).0"        ;;
+        z) new="$oldx.$oldy.$((oldz+MKIT_BUMPSIZE))"    ;;
         *) die "invalid release level: $1"  ;;
     esac
     echo "$new"

src/make.skel

@@ -7,6 +7,11 @@ die() {
 }
 
 
+#
+# Bump size (for vbump_? and release_?)
+#
+MKIT_BUMPSIZE=${MKIT_BUMPSIZE:-1}
+
 #
 # Debug mode (true|false)
 #