Add a Nano installer for Windows

1. Downloads and installs Nano into the users home directory
2. Adds Nano to the path
3. Makes Nano the default editor
Switch from using .bashrc to .bash_profile nano path and editor export
Append exports to end of .bash_profile instead of overwriting

In the process at an explanation of where the lines came from
so that users know they can remove the lines if desired.
Remove testing line
Merge scopatz 'flow-cont' PR 21
Merge scopatz 'vars-types' PR 18
Merge scopatz 'data-struct' PR 20
Merge scopatz 'strings-io' PR 19
added explanation about comparisons, genotype example details
renamed variables, avoiding camelcase
added inline exercise with tests, light-handed change of variable names
Removed math.log example and replaced half-baked examples with more concrete elementary ones.
Expanded examples and converted notebook to v3.
Another version of the code
Merge pull request #35 from ethanwhite/gh-pages

Add a Nano installer for Windows
Simplifying the final example
Merge branch 'gh-pages' of github.com:swcarpentry/bc into gh-pages
Added a link to the python tutor for explaining the stack in a more dynamic fashion
removed nested function calling, IMHO this adds too much information to the basics
Changed position of jocular string comparison