Add mkpretty.sh meta-library

Purpose of this library is to import the actual pretty-printing library
based on FFOO_MKPRETTY value or fall back to mkpretty_plain.

include/mkpretty.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+
+#
+# Name of prerry-printer module
+#
+# Friendly name of module used for decorating output.  For
+# example, if the value is NAME, a mkpretty_NAME module must
+# exist and be importable.  Otherwise mkpretty will fall back
+# to plain, which is also the default value.
+#
+FFOO_MKPRETTY=${FFOO_MKPRETTY:-plain}
+
+
+__ffoo_mkpretty__init() {
+    #
+    # Import proper submodule
+    #
+    if ffoo try_import mkpretty_${FFOO_MKPRETTY};
+    then
+        ffoo import mkpretty_${FFOO_MKPRETTY}
+        return 0
+    else
+        warn "falling back to mkpretty_plain"
+        FFOO_MKPRETTY=plain
+        ffoo import mkpretty_${FFOO_MKPRETTY}
+    fi
+}