Lua5.2 has more strict checking for string.find pattern

Hi, 

When I am testing the cgilua, I got the error about string.find invalid escape:

/usr/local/share/lua/5.2/luarocks/loader.lua:113: error loading module 'cgilua.authentication' from file '/usr/local/share/lua/5.2/cgilua/authentication.lua':
	/usr/local/share/lua/5.2/cgilua/authentication.lua:200: invalid escape sequence near '\?'
stack traceback:
	[C]: in function 'loader'
	/usr/local/share/lua/5.2/luarocks/loader.lua:113: in function </usr/local/share/lua/5.2/luarocks/loader.lua:110>
	(...tail calls...)
	[C]: in function 'require'
	...cgilua-master/examples/cgilua/../authentication_conf.lua:9: in main chunk
	[C]: in function 'xpcall'
	/usr/local/share/lua/5.2/cgilua.lua:174: in function </usr/local/share/lua/5.2/cgilua.lua:173>
	(...tail calls...)
	...�载/source/Lua/cgilua-master/examples/cgilua/config.lua:11: in main chunk
	[C]: in function 'xpcall'
	/usr/local/share/lua/5.2/cgilua.lua:174: in function </usr/local/share/lua/5.2/cgilua.lua:173>
	(...tail calls...)
	/usr/local/share/lua/5.2/cgilua/loader.lua:16: in function 'init'
	/usr/local/share/lua/5.2/cgilua.lua:614: in function 'main'
	/usr/local/share/lua/5.2/wsapi/sapi.lua:53: in function </usr/local/share/lua/5.2/wsapi/sapi.lua:6>
	(...tail calls...)
	[C]: in function 'xpcall'
	/usr/local/share/lua/5.2/wsapi/common.lua:264: in function 'run_app'
	[string "  local app_name, bootstrap_code, is_file = ...."]:67: in function <[string "  local app_name, bootstrap_code, is_file = ...."]:64> 127.0.0.1 Wed Dec  4 23:39:36 2013