* luci/libs/uvl: implement default value option for variable sections

libs/uvl/luasrc/uvl.lua

@@ -1119,7 +1119,7 @@ end
 --- Get the value of this option.
 -- @return	The associated configuration value
 function option.value(self)
-	local v = self:config()
+	local v = self:config() or self:scheme('default')
 	if v and self:scheme('multival') then
 		v = luci.util.split( v, "%s+", nil, true )
 	end

libs/uvl/root/lib/uci/schema/meta/schema

@@ -267,6 +267,15 @@ config variable
 	option datatype	'string'
 	option required	false
 
+# Variable default value (schema.@variable.default)
+config variable
+	option name		'default'
+	option title	'Datatype of this variable'
+	option section	'schema.variable'
+	option type		'variable'
+	option datatype	'string'
+	option required	false
+
 # Variable validators (schema.@variable.validator)
 config variable
 	option name		'validator'