QVI_SCOPE_PROCESS does not what it should in threads

[GuillaumeMercier]

In this sequence of calls:

qv_context_t *ctx;
qv_thread_context_create(&ctx);

 qv_scope_t *base_scope;
 qv_scope_get(
                       ctx,
                       QV_SCOPE_PROCESS,
                       &base_scope
                       );

The scope does not represent what it should, as only the resources usable by the calling thread are reported.
Instead, I would expect the resources usable by the whole process (that is, the one that spawned the thread)
to be reported.

Currently, no instrinsic scope is able to make this distinction.

in issue #41, @samuelkgutierrez proposes to add an intrinsic QVI_SCOPE_SELF that would differ in behaviour
when used by a process or a thread.