Update mayavi_demo edm app

[rahulporuri]

[I'm not sure where else this belongs so this is where i'm opening the issue for now]

The mayavi demo eam/edm application available in enthought/free is out of date. It would nice to

• [ ] Use Python 3 instead of Python 2
• [ ] Use the latest versions of mayavi
• [ ] Use the relevant versions of reverse dependencies for the latest versions of mayavi
• [ ] (optional) Update the version number in the application to match the version number of the package
• [ ] Upload the new app/bundle to enthought/free

PS C:\Users\rporuri> edm app list
name              version        environment              runtime-version
----------------  -------------  -----------------------  -----------------
mayavi_demo       4.5.0          mayavi_demo              2.7.13+3

PS C:\Users\rporuri> edm list -e mayavi_demo
# Packages in environment 'mayavi_demo'
#  prefix: 'C:\Users\rporuri\.edm\envs\mayavi_demo'
appdirs            1.4.3-1     enthought/free
apptools           4.4.0-10    enthought/free
comtypes           1.1.7-2     enthought/free
configobj          5.0.6-2     enthought/free
distribute_remove  1.0.0-4     enthought/free
eam                1.1.0-1     enthought/free
eam_mayavi_app     1.0.2-1     enthought/free
enum34             1.1.6-1     enthought/free
envisage           4.7.0-1     enthought/free
mayavi             4.5.0-7     enthought/free
mkl                2018.0.3-1  enthought/free
numpy              1.13.3-4    enthought/free
packaging          16.8-2      enthought/free
pyface             6.0.0-1     enthought/free
pygments           2.2.0-1     enthought/free
pyparsing          2.2.0-1     enthought/free
pyside             1.2.2-14    enthought/free
setuptools         38.2.5-1    enthought/free
shiboken           1.2.2-12    enthought/free
six                1.10.0-1    enthought/free
traits             4.6.0-1     enthought/free
traitsui           6.0.0-1     enthought/free
vtk                7.0.0-2     enthought/free