Fixed error for importing tfl
Merge branch 'master' of https://github.com/puconghan/plt
Merge branch 'master' of https://github.com/puconghan/plt
Merge branch 'master' of https://github.com/puconghan/plt
Typecheck function implemented by Pucong. Pucong also implemented six seperate check functions for each variable type, including number, url, text, numlist, urllist and textlist.
Merge branch 'master' of https://github.com/puconghan/plt