- Adding tests for package deps
- Adding conflict/override warnings for package deps
- Adding cycle detection for packages
- Adding cycle detection for mixed packages+source
- Fixing internal dependency format of package resources when converted
  to rebar_app_info
- normalizing level-order prioritization to be based on lexicographical
  sort of app names rather than traversal order (which is undefined for
  package deps)
- Fixing tests for source deps for deep cycle detection
- Fixing bugs with source deps
- Relaxed version format checks for test utils

A lot of fixes are combined in there because I didn't want to commit
non-passing code, and many bugs were found when adding the second batch
of tests as part of the original effort.

The case in mind here is due to conflicts, and tests have been added for
this.

- Adding tests
- fixing use of set fetching to find repeated deps and prevent infinite
  loops

On a circular loop rebar3 now fails with `{error, no_sort}`, which is
uncaught and should be handled to consider the issue fully fixed.

- includes logging macros and turns them to functions
- exports customized types

verbosity. Verbosity can be a integer but I am
parsing it as a term. This will work for integers
as well as terms.

command line by converting things to atoms and
splitting up strings where needed.

Templates should only be in ~/.rebar3/templates and the built-in ones,
bar some specific overrides someone may want.

Looking recursively for templates in the CWD (.) may end up searching
nearly forever if the project is being created at the top of a very deep
directory tree, with extremely unlikely chances to find relevant
templates.

It causes more problems than benefits.