Testing Done:
Ran via `G_DEBUG=fatal-warnings gdb --ex run finch3` and verified I was able to make it to the contact list.
Reviewed at https://reviews.imfreedom.org/r/1592/
Title: File Transfer Signals
Slug: file-transfer-signals
## File Transfer Signals
### Signal List
*[file-recv-request](#file-recv-request)
### Signal Detail
#### file-recv-request
```c
voiduser_function(PurpleXfer*xfer,gpointerdata);
```
Emitted before the user is prompted for an incoming file-transfer. Plugins can intercept the signal to auto-accept/auto-reject the requests. To auto-accept the file transfer, use purple_xfer_request_accepted(). To auto-reject, set the status of the xfer to PURPLE_XFER_STATUS_CANCEL_LOCAL.