add .pryrc

bundler-aware .pryrc that takes care of loading code_tracer and its
runtime dependencies(none, at the moment) and development
dependencies(a few) into a pry session.
fix the "one frame ahead bug". closes #1.
Merge branch 'master' into tracer-frame-ahead
Merge pull request #2 from robgleeson/tracer-frame-ahead

fix the "one frame ahead bug". closes #1.