Range fix for Julia v0.3

Range fix for Julia v0.3
Adding functionality to "clean"

Adding clean() which removes zero-area faces and duplicate vertices.
Adding export to OFF format with RGBA colour

Adding export to OFF format with RGBA colour
Updating README.md and removing Progress meter
Adding functions for clean() and exportToOFF(), and range fix for Julia v0.3
Merge branch 'master' of https://github.com/abahm/Meshes.jl
Perturbing vertices on null-faces, removing clean()

Forcing the vertex coordinate to be bounded away from either end of the
segments joining voxel corners
Fixed range

Fixed range
Added importPly

Added a function to read triangular meshes in .ply format.  Note that
the functionality is limited, there are some assumptions made about the
header.   Eventually this can be expanded to insure all .ply files are
handled correctly.
Merge pull request #11 from abahm/master

Added exportToOFF(), perturbed duplicate vertices, and modified Range() to be v0.3 compatible
Added bump parameter to isosurface interface.
Resolved merge conflict.
update travis to run on release and nightly builds