URI Template parser fails with multivalued optional tokens don't have values

[s3u]

Here is an example

https://www.example.org/path1/path2?p1={0|v1}&p2={0|v2}&p3={0|v3}

with values
{
v1: [],
v2: [],
v3: '1,2,3,4'
}

This fails with an error

{"error":"Token itemId not specified. Processed https://api.ebay.com/ws/api.dll?Conditional=","emitted":true}

This is a regression from 0.3

[s3u]

Changes have been checked in - #411