Added `gvac` function for Git verify and clean of Git repo objects.
Refactored `gvca` function to be `gvaca` instead.

- Matches `gvac` naming conventions so that `gvac` works for a single
  project while `gvaca` is for all projects in current directory.
- The use of `gvac` adds a "git vacuum" mnemonic as a nice way to
  think about what is performed by this function while also literally
  meaning: (g)it (v)erify (a)nd (c)lean.
Fixed `gount` alias (now a function) errors for non-Git projects.

- As an alias, it would always execute the commit count (unwanted
  behavior).
- As a function, it only executes when messaged.
Refactored Git project commit count (since last tag) to private
function.

- Simplifies the `gtaila` function.
- Provides customized commit count output with optional prefix and
  suffix support.
- Opens up use in other functions (DRY).
Added `ginfo` function for "Git Info".

- Prints general information about current repository such as local
  configuration, local stashes, local/remote branches, remote URLs,
  file churn, commits by author, total commits, last tag/commit, and
  current status.
- This provides a handy way of wrapping up several functions into a
  single function for "project at-a-glance" focus.
Fixed `_git_commits_since_last_tag` private function to always
fallback to unique commit.

- Resolves errors when attempting to display tags for projects that
  don't have any tags.
- Refactored and removed `git tag` check since it is no longer needed
  with the `--always` option.
Fixed display of commits since last tag.

- Allows the `ginfo` function to display zero commits instead of a
  blank space.
- Updated the `gtaila` function to check for projects with zero
  commits since we still don't want to display projects with no
  activity.