Create GitHub issues based on local templates.

This is useful for pushing, for example, a set of checklists with per-item issues grouped by milestone. The template directory structure is:

.
|-- milestone-1
|   |-- README.md
|   |-- issue-1.1.md
|   |-- issue-1.2.md
|   ...
|-- milestone-2
|   |-- README.md
|   |-- issue-2.1.md
|   |-- issue-2.2.md
|   ...
...

Both the README.md and per-issue files have a summary line (which may optionally include Atx-style headers) followed by a blank line and an optional body. Milestone bodies are plain text, while issue bodies are GitHub flavored Markdown, For example, if you want each of your product to have a joel milestone tracking the Joel Test, you might have a joel/README.md with:

# joel

Keep track of how well the project handles the Joel Test [1].

[1]: http://www.joelonsoftware.com/articles/fog0000000043.html

And per-feature issue milestones like joel/source-control.md:

# Do you use source control?

I've used commercial source control packages, and I've used CVS,
which is free, and let me tell you, CVS is fine...

Of course, you probably can't copy Joel's text wholesale into your issue files, so you'd want to make your own summaries. Then run:

# github-push-issues.py [options] /path/to/your/template/directory

Or:

# github-push-issues.py [options] https://example.com/url/for/template.zip

The latter is useful if you have your template directory structure hosted online in a version control system that supports tar or zip archive snaphots.