xenial fails with this error:

    default: Project ERROR: gstreamer-gl-1.0 development package not found

bionic64 just works.  So move to it :-)

compiling moc/moc_QGCMapEngine.cpp

cc1plus: out of memory allocating 737010184 bytes after a total of 52228096 bytes

This allows for easier iterative development on the virtual machine.

* Add resource config for vmware

* Ignore vagrant directory

* Vagrant config use Qt 5.7

* Vagrant support docker provisioner and use Ubuntu 16.04

* Fix paths for Vagrant build

* Update Vagrantfile to match Travis

* Prefer VM providers over docker

* Get apt packages and environment from travis.yml

* Add graphical environment to Vagrantfile

* Use full Qt 5.7.1 download

* Qt5.5.1 link corrected.

* Qt5.5.1 tarball saves to project's root directory
since qt_deps_tarball used to have prefix of /vagrant.

* Add requests to update machine setup for both Travis and Vagrant

* Vagrant: use config variable in place of static string

* Vagrant: init and update submodules

-general cleanup