improved Windows detection
updated changelog for #901
Merge pull request #901 from mcandre/master

Improved Windows detection
Change `warn_deprecation` to use configurable `deprecation_io`
update changelog
remove internal override of warn
deprecation io
configurable io object
integrate new deprecation io object with config
prevent file escape
rename message to summary
remove stubbing in tests as per @myronmarston's suggestions
change filename to description
fix problem with specs
refactor to use a pure io stream
use string io rather than a tmpfile as per @myronmarston's suggestion
shortcut to setting a deprecation filename
properly stub deprecation warnings
uncessary line removal
remove errant text