Fully resolve head symbols during instrumentation

Thus not mistaking a namespace function called loop for clojure.core/loop
Rework instrumentation to respect local scope

This is done by delaying instrumentation until we can leverage the &env
macroexpansion variable for local scope.

Fixes #21
Accidentally deleted debug line, comments
QA: make tools.reader link reference commit id
[QA] Add a test case for try/catch/finally.
Merge pull request #27 from JacekLach/instrumenting-macro

Delay instrumentation until compilation