* Enable before_wifi_action & after_wifi_action on hasWifiToggle platforms (which is basically all of 'em except naked SDL).
* Decouple restoreWifiAsync from hasWifiManger, because we can do that on other platforms (namely, Kindle. Probably PB, too, but WiFi is already a mess there, and I can't test it).
* Implement restoreWifiAsync on Kindle.
* Properly flag rM as hasWifiManager & hasFastWifiStatusQuery, because it is actually both of those (it uses our wpa_supplicant backend).
* Update the KOSync checks to take these changes into account, to properly disable auto_sync if necessary.
* Really made the Network* event signaling consistent. For realz this time.
* In an effort to make the whole beforeWifiAction framework somewhat usable there, we now assume connectivity is always available on !hasWifiToggle platforms...
* On Kobo, kill WiFi on startup if we detect an inconsistent state...
Untested, not terribly pretty.
The other solution is to slow down the Wi-Fi meny by doing the same
check for the "Wi-Fi connection" checkbox as in the later wifi_status
one...
* Don't enable auto_restore_wifi by default
It's liable to silently murder batteries for no good reason, given that
we prompt to enable WiFi by default when needed, and we otherwise have
no actual need to keep WiFi on in the background.
re #2215 (in particular, this directly contradicts @houqp in
https://github.com/koreader/koreader/pull/2215#discussion_r74696133 ;)).
