Update some of the language in shallow flash tool

Replaced some words to make it more natural for english users and changed some sentences.
Updating some verbiage
Update example
Merge pull request #237 from echangmoz/master

Update example
Merge pull request #233 from bkerensa/patch-4

Updating some verbiage
Merge pull request #232 from bkerensa/patch-3

Update some of the language in shallow flash tool
Merge remote-tracking branch 'mozilla/master' into tinderbox-buildid-support

Conflicts:
	utilities/arg_parse.py