Update: travis, install, gsio.go

I am going to keep the files as multidimensional byte slices as
opposed to converting to a slice of strings. This required me to
write Len, Swap, and Less methods for byte[], and byte[][] which
are referred to as ByteSlice and ByteSliceSlice respectively.

I also updated the install.sh script to set the $GOPATH.

By doing this I ended up simplyfying the .travis.yml script file.