Adding initial version of SQL lesson

Originally developed as a fork of Greg Wilson's Software Carpentry
SQL lecture with the goal of targeting ecologists and using a real
ecological dataset.
Merge pull request #1 from ethanwhite/sql-lesson

SQL lesson and core data files
Added R lessons
Added CONTRIBUTORS file with information on contributions to the R materials
Added info about first workshop and fixed formatting
Added assistant information
Added data conributors
remove mention of for loop

Couldn't see a mention of for loops, perhaps it was in an earlier version, or yet to appear?
Update 01-starting-with-data.Rmd
Update 01-starting-with-data.Rmd
Update 01-starting-with-data.Rmd
Update 01-starting-with-data.Rmd
finally adding shell lessons and cheatsheets for shell and sql
added excel lesson directory
Added CONTRIBUTING.md file for information on how to contribute to the repo
moved files from data into data/biology so there can be other datasets
added directory for python materials
Create ecology_spreadsheets
Merge pull request #6 from cbahlai/master

Create ecology_spreadsheets
added md extension to Markdown file