Moderate improvement/reordering of verbose print statements.
Generalize stitch meshes to still do stitching if there are multiple boundary IDs on a side.
Refactor two copy-paste loops into 1.
stitch_mesh now uses sorted arrays of points rather than an N^2 algorithm for matching points on the stitch surfaces.

It looks the the slowest part of the algorithm is actually doing
N element loops over other_mesh.  Fixing that in next patch.
Removing unecessary loops over the entire mesh and geometric searching. Speeds up stitch_meshes by orders of magnitude.
Fixing one more small issue with stitch_meshes, internal sidesets were not being copied over to the final, stitched-together mesh.
As suggested by @dknez, passing the tol parameter down into the comparison objects used in stitch_meshes.
Merge pull request #89 from jwpeterson/stitch_mesh

Stitch mesh