remove size.go
move SafeFilename to create.go

also, switch to URL encoding
simplify DownloadSector with ioutil.ReadFile
make RSEncode take byte slices instead of io.Writers
add siafiles/util.go
add siafiles/scratch.go
update repair.go
give David another set of braces
Merge pull request #210 from lukechampine/files

siafiles