Allow packages with only one source file

A number of packages have only one source file + __init__.py. __init__.py isn't needed for Python 3, but removing it broke the builds because build.py was assuming there would be at least two files in a package.

Remove update scripts from multi-lib bundle

Merge pull request #13 from adafruit/tannewt-patch-2

No longer include update scripts in the bundle

New CircuitPython Versions

Update builds to 2.2.3 and 3.0.0-alpha.2.

Support namespace packages

• Libraries no longer need to provide __init__.py in packages.
• Bump to 2.2.1.
• Ignore examples and docs folders explicitly now.

Build for 2.2.0 instead of 2.1.0

Now builds bundles for 2.2.0 instead of 2.1.0.

1.0.0!

Actually a minor change that changes behavior enough to warrant a top level bump. This will now cause multi-lib builds like the Adafruit CircuitPython Bundle and CircuitPython Community Bundle builds to fail when a submodule doesn't have a release.

Fix common version case

Fixes version computation when a tag does exist.

A couple more fixes

This fixes a crash when a library has a multiple top-level py files. It'll now print error info and exit with a non-zero status so Travis will fail.

This also fixes an issue with determining a version number when a repo has no tags. It defaults to tag 0.0.0.

Bug fix

Fix builds of libraries which are packages instead of a single module.

Real versions!

Files in zips will now have their version place holders replaced.

For example:

__version__ = "0.0.0-auto.0"

Will become __version__ = "3.0.0" the the git tag is 3.0.0.

For intermediate versions it will be something like __version__ = "3.0.1-alpha.0.plus.1+adaf00" where the 1 indicates its one commit ahead and adaf00 is the first seven characters of the commit hash.