bscr version tests

 - attempt to add bscr.Error, not working too well :(
 - simplified 'bscr version', 'bscr readme'
define bscr.Error and use it to throw exceptions

 - Figured out how to use bscr.Error for throwing exceptions
 - Removed expectedVSgot() and replaced it with self.assertEq()
 - Eliminated a few other minor redundancies
'fl edit' for editing files in place

 - Tests for 'fl edit'
 - Eliminated importlib to keep Python 2.6 happy
Install requirements before backscratcher
Missing doc strings added
Release process

 - Documenting my release process
 - Fixing setup.py to make sure a version file is available before
   trying to open it
Simplify setup.py -- remove pexpect
Add python package requirements
Switch to setuptools from distutil
Versioning as described in http://stackoverflow.com/questions/458550/standard-way-to-embed-version-into-python-package
Trying to get better versioning to work
Getting rid of old .bscr_version file
Update version.py in pre-commit hook
Trying to get pre-commit hook working, should update version.py
Now the pre-commit hook just checks the version and complains if it
doesn't look right. It would be nice to have it actually set it
automatically, but that leaves an updated file not commit. :(
Finalizing the next release.