updated tab-spacing

Updated tab spacing that was not 4 spaces wide on some lines in a few
files

Also added option to pxelinux.0/default for local boot
Merge pull request #8 from psychomario/master

update from original
updated TODO.md
updated DOCUMENTATION.md

moved info about chr(0) under PyPXE services
Merge pull request #18 from mmattioli/master

Tab Spacing Update for PEP8