1.Separate admin settings form in a separate file proxy_auto.admin.inc as suggested by lennartvv
2. Fix grammar at README.txt and proxy_auto.admin.inc as suggested by lennartvv
3. Fix installation instruction at README.txt as suggested by imgio
4. Separate proxy_auto default in a separate file proxy_auto.inc
5. Use strpos() instead of preg_match() at proxy_auto_settings_validate()