add quoteShell to osproc.nim
Deprecate quoteIfContainsWhite in favor of osproc.quoteShell.
Fixed skipFile proc to not skip files that merely start with '.'

Modified removeFile to reset the read only attribute on files before trying to delete.
Merge pull request #736 from Varriount/os/fix-windows-removefile

Fixed skipFile proc to not skip files that merely start with '.'
Use quoteShell in stdlib, where appropriate.
Commented out CAAS testing code.
Merge pull request #743 from Varriount/tests/comment-caas

Commented out CAAS testing code.
Merge pull request #737 from zielmicha/quote-shell

quoteIfContainsWhite -> quoteShell