This adds two new generate-event template variables, dns_suffix (e.g. us-east-1.amazonaws.com) and partition (e.g. aws-cn), and happens to fix a bug where the AWS partition was being used in place of the Kinesis partition key in two templates.

The help text for the SubCommands in generate-event were getting truncated
in the terminal. The help text being displayed was the short_help text and not
the full text. If a click command does not have short_text assoicated, click
will truncate the help text to 45 characters.  We will now set the short_text
to be the full text to allow the contents to be displayed on the screen.

* Update unit tests

- On supplying path for docker, change path to unix style.
- This allows sam-cli to work with docker toolbox on windows.

* fix: remove dependency on pystache

- pystache does not explicitly state it supports py36
- last release was in 2014
- using chevron instead

* fix: use non-patched version of chevron

When installing SAM CLI onto Cloud9 and you don't reset the bash cache, you may see `sam --version` fail with "No such file or directory". Resetting the bash cache will address this.

- Remove source path mapping
- Add a note for the localRoot being based on the where the function
  code resides. This is referenced by CodeUri inside template.yaml
- Add a note on where VS code needs to be opened.

…708)

* fix: allow for stdout and stderr streams to be unbufferred directly.

* fix: only set unbuffered streams when a debug port is set

…713)