Belatedly bump version number

This is in support of the practice of having the version number
in the repository be what it will be upon the next release.  In
particular, the first commit following a release should have the
version number bumped.  In a forthcoming merge, infrastructure for
appending commit hashes to version strings for non-release commits
will be implemented.
Merge branch 'master' into version

Conflicts:
	tulip/__init__.py

The only nontrivial part of this merge is changing occurrences
of the version 1.0b with 1.1a
Version suffix of -dev-{%H,Unknown} for non-release installations

The primary mechanism is a file named commit_hash.txt under tulip/
If it is empty, then the installation is regarded as a release, so
should have a regular version string.  If it is exists and is nonempty,
then its contents are taken to be the commit hash from which the
installation was made, and "-dev-%H" is appended to the version string,
where %H is the hash.  Otherwise (i.e., commit_hash.txt is missing),
"-dev-Unknown" is appended to the version string.

The manner by which tulip/version.py is imported in setup.py is
improved in this changeset.  It now relies on the standard imp package.