* Return shared_ptr from eventloop
* Add -Wdeprecated-copy-dtor warning
Produces a warning if classes don't have explicit copy operations if
they have a user-defined constructor.
This helps us stick to the rule of 5 (kinda, no warnings for missing
move operators).
* Clean up eventloop
* Fix compiler warnings
* Fix fs_event_handle_t name
This is dependent on a PR to xpp that does the same. Newer compilers
(GCC10 in particular) are stricter about which headers provide the
std exception types.
