Surveyor: Make parse function case-insensitive

[john-huang-121]

Make surveyor_tasks.rake parse method to be case-insensitive when it matches the file. This may help avoid capitalization issues when the ENV['file'] filepath name matches the filename in value, but not lettercase.

desc "generate and load survey (specify FILE=surveys/your_survey.rb)"
task :surveyor => :"surveyor:parse"

namespace :surveyor do
  task :parse => :environment do
    raise "USAGE: file name required e.g. 'FILE=surveys/kitchen_sink_survey.rb'" if ENV["FILE"].blank?
    file = ENV["FILE"].include?(Rails.root.to_s) ? ENV["FILE"] : File.join(Rails.root, ENV["FILE"])
    raise "File does not exist: #{file}" unless FileTest.exists?(file)
    puts "--- Parsing #{file} ---"
    Surveyor::Parser.parse_file(file, {:trace => Rake.application.options.trace})
    puts "--- Done #{file} ---"
  end