…tomatically volume mount stage directory into /buildtest in container to allow access to files inside container.

…commands inside container.

how to run a script inside a container and also volume mount inside container

…ners don't need any arguments.

update json schema to remove the 'command' from required list.
add a new buildspecs hello_world.yml that will run the hello-world container.
add documentation on this section

…ssed to container runtime. Update json schema to add support

and add an example test.
Add symbolic links for valid buildspecs for schema validation.
Add one invalid buildspec for testing invalid container platform.
rewrite documentation to include example with 'options' keyword.
refactor codebase by changing if conditions and add support for 'options'