Widget now have a pointer to hexBlocker for use.

Will later change them to work with hexBlocker rather than to
send signals to MainWindow.
added new widget for edge properties
fixed cell count message
It's now possible to set grading on edges.

It's possible to select whether or not grading should be propagated
to parallel (or dependent) edges.
Now reads grading when reading blockMeshDict

Fixed a bug which caused the program to crash after reading hexBlockDict