* docs: Clarify the meaning of WARN state

* Update README.md

* removed version prior to 1.11

* removed references to kubernetes versions prior to 1.11

Strictly, we don't have the changes in 1.13-json but we do have them in 1.13

* Read kubernetes version from environment

Set kubernetes version to the value of the environment variable `KUBE_BENCH_VERSION` if it is defined and the flag `--version` is not specified on the kube-bench command line.

The command line flag `--version` takes precedence of the environment variable `KUBE_BENCH_VERSION` if both are defined.

* Add info about KUBE_BENCH_VERSION to README

* Remove duplicate documentation.

* Add test configuration header back in main README.

* Add missing regex operator in docs/README.

* Fix incorrect description of configuration options bins, confs etc.

* Move description of version auto-detection to main README.

* Use 1.13 in examples since cfg/1.12 doesn't exist

* Remove duplicate sentence about regex

This sentence is now in the docs/README

* Add link to the docs for test YAML definitions

* Update .gitignore

* Update .travis.yml

* Update makefile

* Update .travis.yml

* Update .travis.yml

* Update .travis.yml

* Update README.md

* Update README.md

* Update README.md

* Update makefile

* Update .travis.yml

Without passing in kubeconfig credentials:

```bash
$ docker run --pid=host -v /etc:/etc:ro -v /var:/var:ro -v $(which kubectl):/usr/bin/kubectl -t lizrice/kube-bench:5e6cdfdb master -v 1
I0628 16:52:06.591683    6099 util.go:367] Unable to get Kubernetes version from kubectl, using default version: 1.6
I0628 16:52:06.591822    6099 common.go:74] Using benchmark file: cfg/1.6/master.yaml
...
```
As updated in the README with this fix:

```bash
docker run --pid=host -v /etc:/etc:ro -v /var:/var:ro -v $(which kubectl):/usr/bin/kubectl -v ~/.kube:/.kube -e KUBECONFIG=/.kube/config -t lizrice/kube-bench:5e6cdfdb master -v 1
I0628 16:53:26.784122    7224 util.go:131] No test file found for 1.14 - using tests for Kubernetes 1.13
I0628 16:53:26.784961    7224 common.go:228] Using config file: cfg/1.13/config.yaml
...
```

Add pull requests section
Include instructions for kube-bench version
Other small wording changes

Because we don’t want to put people off running kube-bench altogether in these environments

Values in the version-specific files override the main file

Also describe how tests can be omitted by editing the YAML

Support new configuration options besides --flags:
- JSON file through `jsonpath`
- YAML file through `yamlpath`

These new options are fully backwards-compatible with the existing
tests.

Added a new profile, 1.11-json, that expects a JSON kubelet
configuration file and scores accordingly. This profile is compatible
with EKS.

The root command will run node checks and if possible master checks.
I've also added some Makefile targets to improve local testing and improve the documentation.

Once the master node recommended check:

1.1.12 Ensure that the admission control plugin DenyEscalatingExec is set

has been followed, it is no longer possible to run kube-bench itself using kubectl.

I don't see how kube-bench can check the permissions on files unless it has access to them on the host, so I think we need to be mounting the /etc directory from the host

Signed-off-by: Johannes M. Scheuermann <joh.scheuer@gmail.com>

Specify `-t` to get colour in the Docker output.
Added a note about mounting kubectl or kubelet to get the version.