Util: moved last() to table.last().
Util: added log() and log_traced().
Util: renamed tcheck*() to type_assert*().
Util: added __index-based support in type_assert().
Bind: renamed BindGroup to Group; removed new_group().
conf: changed window size to 1280x720.
Bind: added has_modifier() & has_modifier_any().
Scene/Main: changed mouse1 bind to drag, mouse2 to target.
Added `return M` to all module source files.¹

1: For module (re)initialization purposes (stay tuned).
Util: added trace().
main: added lurker.postswap callback to execute module_reload().
Bind: added redefine_group() and Group.replace().¹

1: Simple way to redefine an existing group (compared to
hacking it up with module_reload() for every module).
Removed src/blah.lua (snuck in).
Replaced Core and Scene bind tables with Bind.redefine_group() calls.