Check validity of constraints' lvalues during PolicyCheckPartial().

The same check existed in the parser so I removed it. Validity of constraints
is now checked in ConstraintCheckSyntax(), copied from ConstraintGetSyntax()
which now expects syntax is already checked.

Also fixed a segfault, so changed the relevant acceptance test to not expect
crash, but just failure.
Fix incorrect context bug and move to paths array
The context "all" is not automatically defined like "any", this caused
the automatic contexts for path definition and path existance to never
be defined. Switching to array for path definitions allows the use of
getindices to build the list of all paths automatically instead of
manually. Top level path variable definition for backward compatibility
still exists.
Wrong check on unit test
Merge pull request #401 from cduclos/master

Fixing a unit test failure.
Allow empty lists at the language level.

Translates empty lists { } => { "cf_null" } in the parser.
Arguably a hack, but much simpler than removing cf_null itself.
RVAL_TYPE_ASSOC is unused, kill it.
Merge pull request #403 from jimis/assoc-kill

RVAL_TYPE_ASSOC is unused, kill it.
Merge pull request #402 from sigurdteigen/feature/language-empty-lists

Allow empty lists at the language level.
add namespaced acceptance tests as per https://cfengine.com/dev/issues/1400
Add another acceptance test for cf_null inputs
Fix segfault in template rendering

Resulting from temporary bundle having no set namespace.
Factor out files_editline.h, constify
Avoid ad-hoc bundles in MakeTemporaryBundleFromTemplate, leak
Ignore Automake test suite files
Move IsReadReady to the proper place
Fix segfault with duplicate handles. Issue #2267
Merge pull request #404 from tzz/tests/array-across-namespaces

add namespaced acceptance tests (try#2)
Merge pull request #405 from baptr/issue-2267

Fix segfault with duplicate handles. Issue #2267
Merge pull request #397 from jimis/bug2230

Check validity of constraints' lvalues during PolicyCheckPartial().
Expose qualified name utility functions in policy.h