cairo/boilerplate

This directory provides code that is common to both of cairo's tests
suites:

 * The test suite for correctness in test/
 * The test suite for performance in perf/

We call it boilerplate as it consists primarily of the boilerplate
code necessary for initializing a backend in order to create a surface
for that backend.

The code here just might be useful for someone looking to get started
writing cairo code to use a particular backend, (but there are no
promises that the boilerplate code found here for any particular
backend is exemplary).