Remove vim editor garbage


There are four binary .swp files introduced by this commit:

https://github.com/InvictusInnovations/BitShares/commit/501cdb4ec73b268fd0c1533eb95d61f9d70d6225

The commit message says "tongbu upstream" and I do not understand what this means.  My best search efforts say these files are garbage created by vim.  So I'm guessing they can and should go.