Fix more partial application in public functions

Found a few more functions using partial application and changed them to
use explicit arguments where it seemed reasonable so that it gives
better function signatures and parameter names in Intellisense.
Fix misspelled function name

Also decided to go ahead and use the same casing convention as the
rest of FAKE and .NET for "fileName".
Improve some logging messages to be more specific and consistent
Fix Copy and CopyTo functions

Previously, the Copy function (which CopyTo also calls) would create a
file in place of the destination directory if the directory did not
already exist. Changed it to call ensureDirectory before copying so
that it automatically creates non-existant directory chains, as is the
behavior of CopyFileIntoSubFolder.
Merge pull request #425 from lasandell/MiscFixes

Misc fixes