* Improve VRML export dialog lay out.
* Make the OK button the default action in the export dialog.
* Make 3D model export work correctly and avoid redundant file copies.
* Fix embedded path separators in wrl files on windows.
* Fix absolute model file path creation in wrl files.
* Clean up VRML export code.
File "rules" has instructional text as comments near top.
2) Convert all text files in repo to LF line ending form.
Any checkout done with "rules" in play will convert the working
tree to native line ending, while keeping repo as LF line ending.