Don't automatically load entries in recyclebin on startup.

Fixes dlech/KeeAgent#83
More informative error messages

When a key fails to load from an entry, the error messsage will now
state which entry(including group path) caused the error. Also, if
there was a problem with SSH key file, it will say whether it was
an acutal file or attachment.

Fixes dlech/KeeAgent#79
Show the source where a key was loaded from.

Fixes dlech/KeeAgent#82
Add support for Cygwin/MSYS socket files

Issue dlech/KeeAgent#80