Fix paths to images; add html/md files
Merge remote-tracking branch 'jeff/master'

* jeff/master:
  added slidify lecture
  rogers reorg
  added slidify lecture
Merge remote-tracking branch 'origin/master'

* origin/master:
  added slidify lecture
  rogers reorg
  added slidify lecture
Merge remote-tracking branch 'github/master'

* github/master:
Lecture on R Profiling
Merge pull request #26 from rdpeng/profiler

Profiler