Installation behind HTTP proxy (inc. authentication)

[taviroquai]

Basically, this issue is to request changes to allow installation behind an HTTP proxy (inc. authentication).

Quick fix was to add PROXY params to cURL (method prepareServerRequest).

Example:

    // Add proxy params
    curl_setopt($curl, CURLOPT_PROXYTYPE, 'HTTP');
    curl_setopt($curl, CURLOPT_PROXY, 'proxy:8080');
    curl_setopt($curl, CURLOPT_PROXYUSERPWD, 'user:password');

[Shuunen]

thx @taviroquai , works nice

[daftspunk]

Relates to #27

[daftspunk]

If this is still an issue, please log it in the main October repo.