Consistent lack of periods in syntax errors.

lib/liquid/lexer.rb

@@ -39,7 +39,7 @@ module Liquid
           if s = SPECIALS[c]
             [s,c]
           else
-            raise SyntaxError, "Unexpected character #{c}."
+            raise SyntaxError, "Unexpected character #{c}"
           end
         end
 

lib/liquid/parser.rb

@@ -59,7 +59,7 @@ module Liquid
         consume(:close_round)
         "(#{first}..#{last})"
       else
-        raise SyntaxError, "#{token} is not a valid expression."
+        raise SyntaxError, "#{token} is not a valid expression"
       end
     end