reproduce_ci_env now keeps the container src up to date when run

Fixes #543
Instead of having to rebuild the container image, each time
you run an image the current vtk-m source directory is copied
into the container. We fix up the files so that if copying
from windows -> linux everything is valid
7 jobs for reproduce_ci_env_warn_about_local_changes in 0 seconds
Status Name Job ID Coverage
  External
passed cdash-buildbot

passed cdash-commit

passed ghostflow-branch-check-master

passed vtk-m-dragnipur-osx-shared-debug+32bit_ids+64bit_coords+clang+tbb

00:10:21

passed vtk-m-dragnipur-osx-static-release+64bit_coords+clang+tbb

00:15:10

passed vtk-m-osheim-windows-shared-debug+ninja-vs-2017+tbb

00:23:11

running vtk-m-osheim-windows-static-release+ninja-vs-2017+tbb

9800:18:59