Rex: Check proxy addresses and filter Javascript

This class can be used to check if a given IP address could be a proxy server responding in ports usually used by proxies. It can generate a log with IP addresses and the information whether it can be a proxy.

It can also check if an array of POST or GET values contains HTML excerpts with Javascript that could be used to perform XSS (Cross-site scripting) attacks.

Rex v1.1 features:
- Proxy port scan can be disabled (in some cases, it blocks users that have port 80 open in their router configuration)
- Added checkspamcop() that checks if a user IP is registered as spammer on Spamcop.net (can be enabled/diabled)
- Function filtraxss() renamed to checkxss() because it really checks the presence of malicious xss doesn't filter anything
- Function checkxss() only accepts arrays
- Added filterxss() that removes or disables tags
- Added checksize_db_data() that can be used to check for data size before inserting in database
- Added filtersql() that escapes special characters in a string for use in a SQL statement
- Portuguese variables renamed to english for better understanding the code to a larger community