Diffing between two entire directories/projects in hg or git?

Question

I inherited a project originally stored in CVS with all the revisions. I made quite a few edits, and I\'m trying to compare all the changes I made in the original directory,

Answer 1

Is there some sort of utility for hg/git where I can do a tree diff... [s]o that say, there's a mark between newly added files, deleted files... [emphasis added]

Yes. We can git diff the current directory against another directory and...

...mark the added, deleted, and modified files:

git diff --name-status --no-index ./ path/to/other/dir

...show only added files:

git diff --diff-filter=A --name-status --no-index ./ path/to/other/dir

... show only deleted files:

git diff --diff-filter=D --name-status --no-index ./ path/to/other/dir

...show only modified files:

git diff --diff-filter=M --name-status --no-index ./ path/to/other/dir

See also: https://git-scm.com/docs/git-diff