Auto merge of #2113 - alexcrichton:weird-filenames, r=brson

This commit is targeted at fixing #2102 via two routes:

1. The dependency on `tar` was upgraded to include more contextual information
   in error messages about why the unpack failed. This should help diagnose
   these sorts of issues that happen in the first place.
2. Packaging crates that have files with odd filenames is no longer allowed.
   An error is returned indicating that the files cannot be packaged as they're
   not cross platform. The currently rejected set of files are non-utf8
   filenames (already present) and those containing characters special on
   Windows.

Closes #2102