Updated package template.
Updated package template.

* Add 6.4 version, as this is now the default one to download on the website.
* raco doc <<name>> should use raco docs <<name>>
* raco is now on the PATH, remove warning
* Change `raco setup --check-deps <<name>>` to `raco setup --check-pkg-deps --pkgs <<name>>` (the former seems obsolete).
* Move `raco pkg install --deps search-auto` to the `install:` section, so that it is done before running the tests
* Move `raco pkg install --deps search-auto cover`, to the `after_success section`, since `raco cover` is run there.
* Fixed .travis.yml syntax (wrong indentation for fields under "matrix:")
* Clone https://github.com/greghendershott/travis-racket.git to a separate directory, not a subdirectory of the current package, as this can cause problems (see https://travis-ci.org/jsmaniac/type-expander/jobs/121099218#L824)

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