added more nginx rewrite rules
added more nginx rewrite rules

In order to make nginx work nicely with uris like /btec/docs/,
/btec/readme and /btec/ext/42.3-user-doc, more rewrite rules have been
added to the suggested configuration in the documentation.

blieque/btec,blieque/btec,blieque/btec,blieque/btec,blieque/btec,blieque/btec