XML Improvements

Additions

• Adds install instructions for Arch linux (#87)
• Add --xmlns option that will tell oq to parse namespaces (#89)
  • NOTE: This will become the default in oq 2.x.
• Add --xml-namespace-alias option to allow normalizing namespaced element names (#89)
  • E.g. --xml-namespace-alias myKey=https://namespace.org would re-write the prefix of any element within the https://namespace.org namespace to be myKey
  • NOTE: The --xmlns option is required to use this
• Add --xml-force-array elementName option that will force the provided element to be parsed as an array even if it only has one item (#93)

Changes

• Various build improvements (#91, #95)

Fixes

• Correctly treat elements with namespace prefixes as unique elements (#88, #90)
• Handle empty jq input on serialization (#83)

Deprecations

• Deprecate Processor#tab and Processor#xml_prolog methods, use Processor#tab? and Processor#xml_prolog? instead