re: #719/assembla - Batch upload breaks off early

* GWToolset.i18n.php
  ** added key 'gwtoolset-no-url-to-evaluate'
  ** changed key 'gwtoolset-dom-record-issue'

* includes/Config.php
  ** changed comments from {boolean} to {bool} for consistency

* includes/Forms/PreviewForm.php
  ** changed $user_options['record-begin'] value from $user_options['record-count'] to $user_options['record-current']

* includes/Handlers/Forms/MetadataMappingHandler.php
  ** added line breaks to code that is > 100 characters
  ** added record-current variable
  ** changed set-up of record-begin variable
  ** changed set-up of record-count variable
  ** re-factored processMatchingElement()
  ** set $_POST['record-begin'] to $user_options['record-current'] instead of $user_options['record-count']

* includes/Handlers/UploadHandler.php
  ** added exception when $url provided to evaluateMediafileUrl() is empty
  ** re-factored getTitle()
  ** re-factored saveMediafileAsContent()
  ** re-factored saveMediafileViaJob()
  ** removed saveMediaFile()

* includes/Handlers/Xml/XmlMappingHandler.php
  ** changed use of $user_options['record-count'] to $user_options['record-current']

* includes/Jobs/UploadMediafileJob.php
  ** added use statements
  ** changed use of error_log() to $this->setLastError()
  ** expanded validateParams() to accommodate new params
  ** passing $this->params['user_options'] instead of $this->params to saveMediafileAsContent();
  ** re-factored processMetadata()
  ** re-located validateParams() within the class
  ** removed class variables

* includes/Jobs/UploadMetadataJob.php
  ** created a processMetadata() method to match similar use in includes/Jobs/UploadMediafileJob.php

Change-Id: Ic82c1a0e73c999d0287ae96a3cf741a0c148a151