Pass Lazybones version into post-install script.

Implements issue #25. `lazybonesVersion`, `lazybonesMajorVersion` and
`lazybonesMinorVersion` are now passed as binding variables to the
post-install script. I have also created a new test template project,
test-tmpl, so that we don't depend on a real one.
Fix main functional test to use Betamax.
Verify that lazybonesMinor/MajorVersion are numbers.

These variables were strings, when they should really be integers. Fixed, and
updated integration tests.
Extend title underline in template README.