Remove old PHP compatibility code

With the recent bump to 5.3, we don't need most of the stuff. I'm still leaving sha1 functions since it's used in Login2 function for old passwords compatibility. Delete them too?

Signed-off-by: Shitiz Garg <mail@dragooon.net>
Add back smf_crc32 function since it's required by Subs-Graphics functions

Signed-off-by: Shitiz Garg <mail@dragooon.net>
Merge pull request #1677 from Dragooon/remove-compat

Remove old PHP compatibility code