AutoTestedSamplesUtil: fix typo in failure message
docs: replace incorrect usages of "as for" with "as per"

These two phrases are commonly confused.  According to dictionary.com and m-w.com, proper usages are:
as for: with respect to; in reference to: <As for staying away, I wouldn't think of it.>
as for: with regard to: concerning: <as for the others, they'll arrive later>; <as for the others, let them get their own dinner>
as per: according to: <as per specifications>
as per: in accordance with: according to <as per your instructions>

The common usage in Gradle JavaDocs is of the form "<some parameter> is evaluated as for <some method reference>", which should instead be "as per".  Almost all instances of "as for" in the codebase are of this form.  There are, however, a few instances that are legitimate usages of "as for".  Those instances have not been changed.
Merge pull request #130 from davidmc24/text-cleanup

Text cleanup