RF: delete objects holding files for windows

Windows complaining about trying to delete files that still have objects
holding onto them.  Delete these objects as we go.
RF: allow for Windows double == longdouble

On Visual studio builds of numpy, longdouble is the same as double.
BF: cannot quote command for Windows

Windows errors for a command with quotes, bless.

Only quote arguments with spaces, hoping the commands don't have spaces.
RF: don't test opening gzip in text mode

It doesn't make sense to open gzip files in text mode, and Windows is throwing
an error, so drop that test.
Merge pull request #273 from matthew-brett/windows-fixes

MRG: fixes to get Windows tests to pass

A few problems with the Windows buildbots:

* Gzip won't open in text mode (it shouldn't anyway);
* A bug in scriptrunners causing the command name to be quoted, which Windows
  does not allow;
* Longdouble is the same thing as float64, need to allow for this in tests
  settting header dtype;
* Windows is fussy about objects letting go of memory maps before deleting the
  file, so delete objects before letting system delete temporary files.