Auto-selects python2 if available in the environment

[lsmag]

Simple patch I made to work on systems where python2 is available. Closes issues #12

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[pcottle]

awesome! however im still getting an error output when running this locally -- think you need to merge error stdout to devnull as well

[pcottle:~/Dropbox (Facebook)/wip/PathPicker:]$ ./fpp 
./fpp: line 27: type: python2: not found

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[pcottle]

Think it works best as:

[pcottle:~/Dropbox (Facebook)/wip/PathPicker:]$ if type asd &> /dev/null; then echo "git exists"; fi
[pcottle:~/Dropbox (Facebook)/wip/PathPicker:]$ if type git &> /dev/null; then echo "git exists"; fi
git exists

[pcottle]

Alright all good, thanks for adding linux support while maintaining our mac support!