First draft of FetcherRefactor.

Have you looked at ConfigUpdate yet? Probably should look at that one first, it would be better to merge that into master before this PR. Having said that: this is a very simple PR. It just breaks fetcher.go (1137ish lines) into 3 files (fetcher.go, url.go, and parse.go see wc output below). Otherwise the code is identical with master.
 
```
pc6a:~/go/src/github.com/iParadigms/walker > wc fetcher.go url.go parse.go 
  618  2381 17768 fetcher.go
  164   657  4589 url.go
  355  1272  9245 parse.go
 1137  4310 31602 total
```