Invalid tar file on windows

[mjalil]

I use Redmine and its plugin gitrevision-download on Microsoft Windows.
tar files that the plugin generates have 2 problems that relate to Grit:

1. Invalid tar file:
   Grit uses win32-open3 on windows and respect to the README of win32-open3 the default mode of output is 't' (i.e. text mode)
   This leads to invalid tar files. output mode should be set to 'b' . in order to this we should call Open3.popen3(command, 'b') in windows
2. Extra ' prepended to file names:
   Also transform_options uses single quotations .e.g. --prefix='pre fix/' that leads to an extra ' prepended to file names e.g. 'pre fix/'my source.cs

I have forked and pushed a patch to Grit and Currently the issue is solved in my working copy