4.1.0 improvments

[wiibaa]

• Improve error handling of xml/xpath parsing
• Minor improvments (see changelog)
• refactor the test file to
  • reuse xml parsing tests
  • group tests logically (I was lost, must admits)

Here is the nex structure of test contexts:

philippe@debian:~/dev/wiibaa/logstash-filter-xml$ grep context spec/filters/xml_spec.rb 
  context "ensure xml parsers consistent report of _xmlparsefailure" do
    context "XMLSimple validation" do
    context "Nokogiri validation" do
  context "parse standard xml" do
    context "using formatting options" do
      context "forcing_array" do
      context "suppress_empty" do
      context "force_content" do
  context "executing xpath query on the xml content and storing result in a field" do
    context "standard usage" do
    context "xpath expression configuration" do
    context "namespace handling" do
  context "plugin registration checks" do

[wiibaa]

@suyograo do you want to continue cleaning up this plugin ?