InSync is the opposite of RequiresRestart...
bug fix: allow folder names up to length 64 in leveldb

When extracting a folder name from the byte slices used as database
keys, bytes.IndexByte() is used to find and remove trailing 0 bytes.
In case the folder name is 64 bytes long, bytes.IndexByte() returns
-1.  Before this change, syncthing crashed in this case with an
out-of-bounds slice access.

The commit fixes the problem and also introduces a test case which
checks for the presence of the bug.
Remove dead code
Test case and goleveldb fix (fixes #740, fixes #796)
Archive a copy of config.xml when the format changes
Threshold for existing languages to be included (75%)
Translation update
Merge branch 'master' of https://github.com/syncthing/syncthing into timeout