Mentions min CPU limit change in backward incompatibilities section.

revert change to increase min. CPU resource value from 20 to 100

Add missing token option for nomad run command

Change 'CoreOS rkt' to just 'rkt'

In the commit 622d3ddb
"Fixed test and moved constants into standalone func" the minimum CPU
resource value for a job was increased from 100 to 20.

This can break the nomad setup for people that used lower CPU
values and are at the maximum MHz value of the available CPU on a
machine.
Change the minimum back to 20 MHz to ensure downwards compatibility.

CoreOS initiated the project but it is now under the CNCF banner and includes many contributors and core maintainers that are not at CoreOS.

Search endpoint forwarding

code review fixups; add changelog

Services should not require a port

Fixes #3673

Add Spark configuration properties for ACL token and namespace

Skip tests that require root when not root

Add Spark configuration properties for ACL token and namespace. Remove spark.nomad.job property (deprecated in favor of spark.app.id).

Update eval modify index as part of plan apply.

Minor fixes and additions to Resources page

Travis: Lock down nodejs version

The new Travis Trusty image uses node 8 (latest LTS) as the default.
Node 8 is incompatible with some modules used for the UI.

Update template.html.md Vault template example

The change updates the Vault example within the Environment Variables section to use the `.value` notation rather than the `.key` notation. This is because the example is calling a specific secret key and populating an env var with this; meaning the value of the secret is required over the value.

Also skip Chown on allocdir migration on Windows and when non-root.
Windows doesn't support it, and it will always fail as a non-root user.

Fix minor formatting issue on Docker docs page