Ignore empty settings in version-check

[grtjn]

Ignore <rewrite-resolves-globally>@ml.rewrite-resolves-globally</rewrite-resolves-globally> entirely if propery is empty..

[grtjn]

Just a matter of adding [fn:string(.) != ''] when data is retrieved

[grtjn]

Correction, empty values are suppressed, replacing vars goes wrong. sample ml-config is bad. This:

<rewrite-resolves-globally>@ml.rewrite-resolves-globally</rewrite-resolves-globally>

Should be:

@ml.rewrite-resolves-globally

[grtjn]

Additionally:

if @properties['ml.rewrite-resolves-globally'].present?

Should be:

if !@properties['ml.rewrite-resolves-globally'].nil?