On Lua coroutine resume, pass correct number of arguments
Add lua { cache period = 30s } to lwan.conf
Use alternative method calling syntax to obtain query parameters

Initially, accessing query parameters would create a userdata with a
metatable implementing __index to fetch the variable. This proved to be
too much too complex, so a simple function with a string argument is
what's going to be. Just use an alternative syntax to sort of make it
look like an associative array subscription.
Add server-sent-event wrapper to lwan-lua
Use strbuf_set_static() to send chunks/events in lwan-lua

There's no need to copy these strings again, as send_chunk/send_event
will call writev() immediately.
Remove FIXME from lwan-lua request_param_getter()
Add comment about cache leakage on lua module shutdown
Use 4-space indent in test.lua
Add SSE example to test.lua
Use a helper function in test.lua::handle_get_root()
Do not pass PATHS to techempower/CMakeLists.txt::find_library() call
Try harder while looking for Lua libraries

pkg-config naming is a mess across libraries, so try harder while trying to
find a suitable match.

Hopefully fixes #70.
Use message(FATAL_ERROR ...) instead of message(FATAL ...) in CMakeLists.txt files
Cleanup mmap_serve() by calling serve_contents_and_size() only once
Add a comment about a possible race condition in the cache module