Merge pull request #2 from KKescondida/homework

Homework
I reorganized the directory structure to keep files from different projects in different directories.
xls files in pyLink (I also took the liberty to change the name so we can distinguish it from the original pLink) need to be replaced with csv files
Merge branch 'homework' of github.com:eco32i/nlpy into homework
change files to .csv from .xls
Merge pull request #3 from KKescondida/homework

change files to .csv from .xls
Fixed directory structure - moved pLink_xls directory to pyLink. Removed .DS_Store file - it should be included into .gitignore
Merge pull request #4 from eco32i/homework

Homework