Small edits to novice R lesson on loops.
Added comment in code to highlight the bad line in the loop that grows the object.
Updated indenting and added explicit return statement in supp lesson on loops to make it consistent with the main lesson.
Fixed a few more indentations.
Started new lesson on flow control with R that doesn't include image manipulation.
Added motivating section on saving plots.
Added section on conditional statements.
Added some extra explanation on boolean variables and logical tests.
Added challenge for conditional statements section.
Added section on automatically generating figures.
Added objectives and key points.
Added next steps.
Merge branch '04-cond' of github.com:jdblischak/bc into lessons
Merge branch 'lessons' into gh-pages