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
Add images for lesson
Added info about man command and file naming with whitespaces
Started working on examples with bio data
Added sublime to text editors
Merging Christie's file ecology_spreadsheets.md
Splitted lessons into files and put them into eco-examples directory
Moved img to main directory and added bad_null example image
Added file to img and updated wording
Merge pull request #8 from apawlik/excel-lessons

Splited Excel tutorial into separate lesson-files and added img directory
Linked lessons
Create README.md
Linked lessons between themselves
Marking work for tomorrow
Linked lessons in lesson 4
short introduction to Python - initial file
First revision of first part of first lesson. Next revison will come tommorow, hopefully
Merge pull request #10 from apawlik/excel-lessons

Linked files between themselves