Julia 1.0!

PkgTemplates works on Julia v1.0 now!

Changes to the API:

• The keywords years, requirements, and gitconfig to Template are gone
• The keyword ssh in generate has been moved to Template
• The keyword force to generate is gone

Changes to Templates/package generation:

• Generated packages have Project/Manifest.toml for the new package manager

Changes to plugins:

• Documenter plugins (GitHubPages) use @autodocs for generated documentation (#14)
• TravisCI generates URLs on travis-ci.com, not .org (#18)

The documentation has been updated, in case I missed anything.