pdf_XXX_t variables creation (Was: [pdf-devel] time module unit test cases)

[jemarch]

   Explaining a little bit deeper, for example glib (I am a glib fan)
   normally allocates the memory inside the functions and the user has
   to call the appropriate functions to free them, for example:

That is a good approach and we are using it in many of the pdf_xxx_t
"objects" in the library (such as pdf_stm_t or pdf_text_t).

To create a pdf_XXX_t variable you usually do:

pdf_XXX_t myxxx;

myxxx = pdf_xxx_new (parameters...);

and then, in order to dispose any used resources:

pdf_xxx_destroy (myxxx);

That schema works for both pointers and structures (heap or stack
memory) and the details are not exposed to the user.

I will change the implementation of both pdf_list and pdf_hash to
follow that convention.