Seems like there could be a defect in uClibc making errno not
thread-local. Don't rely on errno value but check function return value
instead which is a better failure indicator.
Return errors from `tr_loadFile` and `tr_variantFromFile` via tr_error.
Fix `tr_sessionLoadSettings` to not fail on Windows if settings.json
does not exist.
1. add the option the code to be used under GPLv2 or GPLv3; previously only GPLv2 was allowed
2. add the "proxy option" as described in GPLv3 so we can add future licenses without having to bulk-edit everything again :)
3. remove the awkward "exception for MIT code in Mac client" clause; it was unnecessary and confusing.
I'm less certain that these are unneeded because networking APIs seem to have more variation between platforms, but it's better to remove the cruft and then add back whatever headers $PLATFORM users complain about, than to not remove the cruft at all...
The Berne Convention says that the copyright year is moot, so instead of adding another year to each file as in previous years, I've removed the year altogether from the source code comments in libtransmission, gtk, qt, utils, daemon, and cli.
Juliusz's copyright notice in tr-dht and Johannes' copyright notice in tr-lpd have been left alone; it didn't seem appropriate to modify them.
