The creation doesn't need to be separated from the SyncEngine anymore.
This allows the SyncEngine to be created in fewer steps if we want to
use it in tests.
This moves most of the direct csync code from Folder into the SyncEngine.
The exclude file logic for the context has been wrapped using the
existing ExcludedFiles class as well.
Given that we control all call sites, the only way that this can fail is during
OOM. Also remove the code in csync itself to make sure that it's obvious that
any new error case wouldn't be handled by call sites.
So we avoid lots of memory allocation.
We can work with char* directly since both the pattern and the file
name are in UTF-8 and there is no need to understand unicode for
such pattern.
(In fact, '?' would not match anyore non-ascii characters, but I
don't think that's a problem. I don't think anyone use '?' in its
exclude list. And the two allocations per call to csync_fnmatch are
really worth getting rid of)
This function only checks the full path and the basename and is thus
around 7x faster. It is very useful in a csync_update context where
we know that the leading dirs have already been checked for exclusion.
