Windows port

I've made a few changes to support installing on Windows.

In addition, ran into couple of bugs:

- replaced used of single quotes with double quotes in Tcl strings; for example

```
set os_path_sep ':'
```
should be 
```
set os_path_sep ":"
```
- TestObj::execute was using a exception object outside its scope in the verdict == FAILURE case.

/Ashok
Exception class $e is not in scope here