Revert "Merge pull request #185 from ISSIntel/liquid-utf8"

This reverts commit c5dfcd29b0, reversing
changes made to f7d1e1d0c1.

lib/liquid/block.rb

@@ -3,7 +3,7 @@ module Liquid
   class Block < Tag
     IsTag             = /^#{TagStart}/o
     IsVariable        = /^#{VariableStart}/o
-    FullToken         = /^#{TagStart}\s*(#{WordRegex}+)\s*(.*)?#{TagEnd}$/o
+    FullToken         = /^#{TagStart}\s*(\w+)\s*(.*)?#{TagEnd}$/o
     ContentOfVariable = /^#{VariableStart}(.*)#{VariableEnd}$/o
 
     def parse(tokens)