Missing HazMap.cs

Forgot this file and lost the work I had done on it.
So redone it and a few more changes.
* Fixes crash on save dialog cancel
* Removed my failed crash prevention from
clipboardToolStripMenuItem_Click() (was moved to readscan.cs)
* Moved openfilediag() up other openToolStripMenuItem_Click()
* Added same check to textFileToolStripMenuItem_Click() as I did for
clipboardToolStripMenuItem_Click()