Maruku "Email" Header Detection

The Regexp, used in Maruku to detect "email"
headers (used, e.g., for S5 slideshow metadata)
could, for some inputs, interact badly with
Instiki's Chunk Handler.
Fixed.

vendor/plugins/maruku/lib/maruku/string_utils.rb

@@ -46,7 +46,7 @@ module MaRuKu; module Strings
 	#
 	def parse_email_headers(s)
 		keys={}
-		match = (s =~ /\A((\w[\w\s\_\-]+: .*\n)+)\s*\n/)
+		match = (s =~ /\A((\w[\w \t\_\-]+: .*?\n)+)\s*?\n/)
 		if match != 0
 			keys[:data] = s
 		else