Fix meta tags parser

Summary:
This approach isn't satisfactory: it uses regexp instead to parse tokens.
But it's carefully tested and good result.

Regexp by Bobble Bubble.

Test Plan: Check tags from http://www.footofeminin.fr/LFP-Nathalie-BOY-DE-LA-TOUR-une-femme-elue-a-la-tete-du-foot-pro-francais_a13077.html

Reviewers: dereckson

Differential Revision: https://devcentral.nasqueron.org/D717