Update Protocol.php

case-insensitive, may be "upgrade"
update strpos
Merge pull request #31 from feifengxlq/master

http header "connection" may be case-insensitive
Correct use of gmp_init()

As suggested by @Rupert-RR
Merge pull request #36 from varspool/bugfix-issue-34

Correct use of gmp_init()
Correction of receive spelt recieve in 3 comment instances.
Modified Protocol and Connection to make all non-web-sockets headers and
all query parameters used in the original UPGRADE HTTP request available
in the Connection object (for example to determine language preferences
from query parameters or cookies).
Updated documentation to reflect these changes.
Fix whitespace and line ending inconsistencies
Merge pull request #38 from varspool/feature-headers

Fixed whitespace on Add_access_to_headers_from_the_original_web_sockets_HTTP_request branch