gitignore, dfu-util directory

.gitignore files merged and cleaned prior to root directory .gitignore
file.
dfu-util didn't start when doing make with Cygwin.
Submodule dirty ignore

Prevent dirty OwlPatches submodule commits when replaced with a more
recent content in order to make a firmware with the very last version of
OwlPatches.
Merge branch 'master' of github.com:sgissinger/OwlWare into sgissinger-master
Merge branch 'sgissinger-master'