Added ps cheatsheet
Marked comments in the example cheatsheet
add show to apt-cache cheatsheet
Merge pull request #34 from stvnwlsn/mychanges

add show to apt-cache cheatsheet
Merge pull request #33 from albertojacini/fix_readme

Marked comments in the example cheatsheet
Merge pull request #32 from albertojacini/ps_cheatsheet

Added ps cheatsheet