Add *.swp to .gitignore.
Fix silly bug when walking.

Prior to this change there would be duplicate parameters in the URL
for each walk. The first time we would fetch:

/api/v1/campaigns/?api_key=...

Then the next argument would contain all the parameters, and we would
blindly append our own parameters to it. Fix it by not using parameters
when walking.
Merge pull request #5 from wxsBSD/walking2

Walking2