Requires gcc version 4.7 or higher

Avoids the clutter and maintenance effort associated with providing the
function signature string.

This reverts commit c5bea524.

This reverts commit b18f6cc1.

Basic featureEdgeMesh functionality.  Dropped intermediate edgeMesh, not serving any purpose, moved io into featureEdgeMesh.  Reads and writes from file.  Can construct self from surfaceFeatures object.  This functionality added to surfaceFeatureExtract, writing to constant/featureEdgeMesh.

Renamed edgeMesh -> primitiveEdgeMesh, featureEdgeMesh -> edgeMesh.  Will use a new, derived featureEdgeMesh class for cvMesh where there is additional functionality, i.e. querying normals adjacent for features edges and points.

- can use 'XX.empty()' instead of 'XX.size() == 0', 'XX.size() < 1' or
  'XX.size() <= 0' or for simpler coding.
  It also has the same number of characters as '!XX.size()' and /might/ be
  more readable

- many size checking had 'XX.size() > 0', 'XX.size() != 0', or 'XX.size() >= 1'
  when a simple 'XX.size()' suffices