Meta Tag Handling Improvements

[jdonmoyer]

• Add performance improvement to only convert meta tag match to lowercase once in the for loop
• Add an updateMetaTag method that will only store the meta tag value if it is non-null and non-empty; This fixed issues where bad descriptions were being pulled in cases where multiple 'description' meta tags were found and the last one had no value. See www.fandango.com for an example case where this occurs.