Also replace __MKIT_SELF_VERSION__ token

MKit current version; this can be added in templates to aid maintenance
and debugging issues related to MKit.

src/include/build.sh

         echo "s|__MKIT_PROJ_PKGNAME__|$(ini 1value project:pkgname)|;"
         echo "s|__MKIT_PROJ_TAGLINE__|$(ini 1value project:tagline)|;"
         echo "s|__MKIT_PROJ_VERSION__|$(get_version)|;"
+        echo "s|__MKIT_SELF_VERSION__|$MKIT_VERSION|;"
     } >> "$script"
     perl -wp "$script" || die "expand_variables failed"
     rm "$script"