Ignore HTTP 100 headers
Ignore HTTP 100 headers

Some responses end up prefixed by a "HTTP/1.1 100 Continue\r\n\r\n"
which blows up the XML parsing so we need to skip over that portion.

Fixes #86

phpdave/recurly-client-php,developer-devPHP/recurly-client-php,cgerrior/recurly-client-php,lyrixx/recurly-client-php,developer-devPHP/recurly-client-php