Refers to #3

Allow setting the log level explicitly from "Warn", "Info", "Debug" or
"Trace" in the configuration.

Default is "Info", fallback for invalid settings is "Debug".

Fixes #34

Otherwise it will be missing when a grace cleanup email is being sent in
the startup phase.

Refers to #31

Fixes #31

Try to move the corresponding transfer package out of the processing
location to prevent it from being picked up again and producing the
same problem again, move it to the error location instead and reset the
transfer variables.

If a new directory is found in incoming but the move operation to
processing failed for some reason, the timestamp and username
directories (and potentially some partially moved data?) would remain
in processing. To prevent confusion about those "incomplete" transfer
candidates they are moved to the "ERROR" location.

Use a list to keep track of directories in the incoming directories that
couldn't be moved to the processing location and ignore them until the
service is restarted.

Refers to #9

Refers to #3, #11, #15

Refers to #18

Refers to #18

Refers to #18

Restoring the "heartbeat" functionality without the overhead of
serializing the XML every second.

Closes #9

Currently there are no references to the object before a transfer has
started, so it is safe to only initialize it in the StartTransfer()
method.

Refers to #3, #4

Refers to #4

Having the total progress is much more useful than for the individual
files, especially for transfers with many files.

Closes #26

Refers to #3

Refers to #3

All projects (and namespaces) should start with an "ATx" prefix, having
a capital "AT" and a lowercase "x".

Refers to #25

Refers to #3, #4