hdf5_msb

[svn-r15288] Purpose: Project Cleanup / Support directories with spaces

Description:
On Windows, we manage dynamically-generated code through "post-build" steps in Visual Studio.  However, the command for it wasn't checking to see if the code already existed, so it was re-generating in each build (and thus re-generating all dependencies).  To overcome, we simply check if the source file exists before generating it.

Also, put all paths inside quotes so we can handle directory names with spaces.

Tested:
VS2005 on WinXP