Replace gocql/gocql imports with scylladb/gocql

[rkuska]

Also rename the go.mod to scylladb/gocql to make installable with go
modules.
This is needed for a fork as you want to use internal modules within the
package - in case you modify any of them and also have the possibility
to install both fork and the original upstream version.

It seems like issues are turned off so I couldn't create an issue for this. We are using go modules and with these I wasn't able to install your fork version.

 $ go get -u github.com/scylladb/gocql/
go: finding github.com/scylladb/gocql latest
go: github.com/scylladb/gocql@v0.0.0-20181115114908-435701b4f3c0: parsing go.mod: unexpected module path "github.com/gocql/gocql"
go get: error loading module requirements

I would expect the fork to carry a different module names as somebody might want to have installed both fork version and also the original one. And also, I would expect in within the package to import its modules.

[rkuska]

Important to note, I didn't test it, I just meant to open a discussion with my PR. If needed I can push same changes to my repo (change scylladb -> rkuska) to test it out.

[mmatczuk]

@rkuska please do not change import paths, tools (like gocqlx) will not work with it. Please take a look at https://github.com/scylladb/gocql#installation. Unfortunately new go modules do not support forks yet [1], maybe you may prove me wrong.

[1] golang/go#26904

[rkuska]

I think I managed to find out how to use forks with go modules. I will close this PR (as you are obviously right, I forgot about depending packages), test out the solution I found and create an issue for further discussion in case it will work as README will need an update.

[mmatczuk]

Hi @rkuska,
I rebased master to the current gocql version, I also updated the README file with configuration section. If you have anything to add please share.

[rkuska]

Hi @mmatczuk I opened #4 where I explained how to use fork with go modules would like your approval or check before creating the PR.