A bunch of generalized code cleanup. (etr#322)

* Replace static_cast<T>(-1) with std::numeric_limits<T>::max().

* Move setting of http_request::cache out of the contructors.

* Remove all uses of this->

* Cleanup some extra ().

* Use the calling signiture for uri_log as defined by the docs: https://www.gnu.org/software/libmicrohttpd/manual/html_node/microhttpd_002dconst.html#index-logging

* Revert setters.

A bunch of generalized code cleanup. (etr#322)

* Replace static_cast<T>(-1) with std::numeric_limits<T>::max().

* Move setting of http_request::cache out of the contructors.

* Remove all uses of this->

* Cleanup some extra ().

* Use the calling signiture for uri_log as defined by the docs: https://www.gnu.org/software/libmicrohttpd/manual/html_node/microhttpd_002dconst.html#index-logging

* Revert setters.