cli: Allow optional parameters to commands

This will enable use to make layers optional parameters for normal
client use (non-direct)

Signed-off-by: Michael Ikey Doherty <michael.i.doherty@intel.com>
cli: Enable retrieval of keys without specifying the layer

This is required to expose any problems at this stage with automatically
determining the retrieval layer, and that all content is correctly serialized.

Signed-off-by: Michael Ikey Doherty <michael.i.doherty@intel.com>
shared: Fix free() of unallocated response_store

When a message cannot be deserialized, response_store is unallocated,
however we're still trying to free it in end:, this commit fixes
this behaviour.

Signed-off-by: Michael Ikey Doherty <michael.i.doherty@intel.com>
Fix the minimum size again.

Incorrect assumption being made about size, we're only interested in
the size of a buxton *control* length, which is a uint32_t and a size_t
The rest is part of a buxton message itself.

Signed-off-by: Michael Ikey Doherty <michael.i.doherty@intel.com>
cli: Minor fixes to command handling

Signed-off-by: Michael Ikey Doherty <michael.i.doherty@intel.com>