Use PHP's http_build_query instead of custom function, #162

This fixed the issue in #162 about some long where statements not working, at least on the machines I tested it with:
PHP [v5.3.28] with Curl [v.7.30.0] on Windows/IIS
PHP [v5.5.11] with Curl [v.7.36.0] on Windows/IIS
PHP [v5.6.0] with Curl [v.7.36.0] on Windows/IIS
PHP [v5.4.24] with Curl [v.7.30.0] on Mac/Apache