Fall back to default mode if not specified in INI

If for certaiun group a mode is not specified, fall back to
a value inhertited from environment, or eventually to 644.

mkit/include/deploy.sh

@@ -29,6 +29,7 @@ install() {
       | while read group;
         do
             mode=$(ini 1value "modes:$group")
+            mode=${mode:-$MKIT_DEFAULT_MODE}
             ini lskeys "files:$group" \
               | while read src;
                 do

mkit/include/mkit.sh

@@ -9,6 +9,7 @@ MKIT_INI=${MKIT_INI:-mkit/config.ini}
 MKIT_INI_EXPAND=2
 MKIT_PKGNAME=$(ini 1value "ENV:PKGNAME")
 MKIT_PROJNAME=$(ini 1value "ENV:PROJNAME")
+MKIT_DEFAULT_MODE="644"
 
 configure() {
     #