Issue #2046039: Fix issues with README.md

  - Outdated info about petitions submission limit
  - Fixed line endings and line breaks
PT-970 - Added a function to sanitize strings for XML output

	modified:   UPDATE.txt
	modified:   build-petitions.make
	modified:   drupal-org.make
	modified:   modules/custom/api_users/api_users.module
	modified:   modules/custom/petitions_data/classes/PetitionsBase.class.inc
	modified:   modules/custom/petitions_data/classes/PetitionsIndexMongoRaw.class.inc
	modified:   modules/custom/petitions_data/classes/PetitionsRetrieveMongoRaw.class.inc
	modified:   modules/custom/petitions_data/classes/SignaturesBase.class.inc
	modified:   modules/custom/petitions_data/classes/SignaturesMongoRaw.class.inc
	modified:   modules/custom/petitions_data/petitions_data.info
	modified:   modules/custom/petitions_data/petitions_data.module