Added constant for __YIQI_INSTRUMENTATION_TOOL_ACTIVE, added a test to
ensure that this env is set
Split out the argv and env determination from RelaunchIfNecessary and start
rewriting that function in terms of those other split out functions
Get the tests passing
Remove empty namespace
Split the ArrayFitsMatchers matcher out into its own library
Deliver the first integration tests, split out shared re-execution data
into a new library
Bootstrapped acceptance tests and get the main part of Yiqi working -
namely, re-execution under some instrumentation tool

Fixes #3