Correlated renames split across batches on Windows

[smashwilson]

Associate renames that are split across event batches on Windows by storing the old path in the subscription.

Fixes #84, at least partially.

[smashwilson]

Unfortunately, Windows seems to have a hard time reporting renames as renames:

[> file C:\Users\smash\AppData\Local\Temp\churn-1171016-11276-1bpje25.lce4\root\directory-30\directory-213\file-141.txt => C:\Users\smash\AppData\Local\Temp\churn-1171016-11276-1bpje25.lce4\root\directory-30\directory-86\file-214.txt]

[..\src\worker\windows\windows_worker_platform.cpp:326] Event at [C:\Users\smash\AppData\Local\Temp\churn-1171016-11276-1bpje25.lce4\root\directory-30\directory-213\file-141.txt] FILE_ACTION_REMOVED unknown.
[..\src\message_buffer.cpp: 31] Emitting filesystem message [Message [FileSystemPayload channel 1 unknown deleted C:\Users\smash\AppData\Local\Temp\churn-1171016-11276-1bpje25.lce4\root\directory-30\directory-213\file-141.txt]]

[..\src\worker\windows\windows_worker_platform.cpp:326] Event at [C:\Users\smash\AppData\Local\Temp\churn-1171016-11276-1bpje25.lce4\root\directory-218\directory-86\file-214.txt] FILE_ACTION_REMOVED unknown.
[..\src\message_buffer.cpp: 31] Emitting filesystem message [Message [FileSystemPayload channel 1 unknown deleted C:\Users\smash\AppData\Local\Temp\churn-1171016-11276-1bpje25.lce4\root\directory-218\directory-86\file-214.txt]]

It does have better luck with directories than files. There isn't a whole lot that I can do about this one short of tracking every inode.

[smashwilson]

Not too shabby:

renamed total: 86
 - exact: 48 (55.81%)
 - unknown: 0 (0%)
 - split exact: 38 (44.18%)
 - split half unknown: 0 (0%)
 - split full unknown: 0 (0%)
 - unexpected: 0 (0%)
 - missed: 0 (0%)