HTTP: add support for OPTIONS method

Signed-off-by: Nil Croustillac <nilcroustillac@gmail.com>
Signed-off-by: Eduardo Silva <edsiper@gmail.com>
Core: initialize clock before load plugins.

Some plugins could use the core clock API or buffer cache to perform
some timing operations (or format strings), before this patch the plugin
would crash as the clock was not initialized before spawn it.

This patch moves the sequential initialization before to load the plugins.

Signed-off-by: Eduardo Silva <edsiper@gmail.com>