(MAINT) Release Mergeback v0.7.0

PSCredentials are handled specially from other CIM instances and should
not be parsed twice for the DSC invocation script; the CIM instance parsing
is redundant.

Prior to this commit the variables for credentials and cim instances
were instantiated prior to the definition of the block for that
credential or instance; this caused the variable interpolation step
to replace the value definition with a self-referencing variable which
would always be null, and thus fail to correctly instantiate.

This commit moves the code for variable instantiation to *after* the
credential or CIM instance is created, meaning only subsequent calls
will reference the variable.

(MAINT) Minor fixes to CIM instance handling

…ay-check

(GH-84) Fix empty array parameter check

Prior to this commit the dsc_base_provider checked for the legacy vendored
DSC module path before the new, specific path; in cases where the modules
installed are a mix of old and new path, the old path will _always_ exist,
even if the specific module is not there (because it is looking for the
*container*, as the container can hold any number of vendored modules).

This commit inverts the search order, seeking the most specific location
*first* and falling back to the general location if needed.

Prior to this commit the comparison in the DSC base provider for
values on the node vs values in the manifest was a simple equals
check; this works for non-enumerables and for enumerables *so long
as* the enumerables are in the same order.

This commit corrects the check to sort the enumerables so that the
comparison is done purely on the values, not the order, as PowerShell
does not care about the order of items in a hash or array.

…e-canonicalization

(MAINT) Correctly canonicalize enumerable values in dsc

…-path-first

(MAINT) Ensure vendored path check works with mix of module builds

(MAINT) Prep for 0.7.1 release