Add ability to measure

[cdplayer]

Wondering if it's possible to add the ability to measure from faces, vertices, points to others. Maybe some log system of each measure selected.

Also like the idea of a simple clean interface that you only turn on attributes you have a need for. ie issue#41

[mwestphal]

There is a similar issue in F3D, so it probably needs to be fixed in F3D first: f3d-app/f3d#119