Remove unused files

It would appear that the main project was moved into core sub-directory, and
these files didn't get cleaned up.
Correct issue with publishing

Main project doesn't have anything to deploy, and doesn't have config. This
causes a warning when building the project.

Provide the config that is common across all projects in this config file,
but no config for the main project is required.
Fix scm url's

All were pointing at project.name, when in fact they all exist in the same
serenity-core repository
Merge pull request #7 from mikezx6r/master

Gradle build cleanup
Use gradle-git for version and tagging

    === If local repository is dirty
        -Always builds a SNAPSHOT version.
        -Will complain that 'Stage {} is not one of [SNAPSHOT] allowed for strategy snapshot.'

    === If local repository is not dirty
        Set release type using property release.stage. Valid values are:
            -milestone
            -rc
            -final
        milestone creates a tag with the next version from tag + -milestone.#
        rc similar, but uses rc. Cannot create a milestone after an rc
        final creates a version with no endings

    If want to use ssh authorization, must ensure ssh-agent contains correct key for repository being worked on.
    If you experience issues, try ssh-add -D to clear identities and add the one identity for the repo in question.

    The release tags the current commit, and pushes to the remote repository. It does not check if there's a new commit, so only use it if you really need to.

    gradle bintrayUpload release -Prelease.stage={milestone|rc|final}