Fix left quotes
fixed gradient section
updates to cheatsheet
added NNs and fixed some earlier material
Updated decision trees and added boosting section
strengthening NN section
strengthening NN section
fixed some merge conflicts
Added more extensions.
Merge branch 'master' of https://github.com/achalddave/EECScheats

Conflicts:
	189cheatSheet.tex
Merge branch 'master' of https://github.com/kvsikand/EECScheats

Took the clustering section only.
NN almost done
Merge branch 'master' of https://github.com/sharma409/EECScheatsheets
pushing unfinished NN section for update by Eddie
fit NN on one column. submitting for peer review