Previously literal C code blocks from the initial definition section
(before state sets) went before everything else, and those from the
final definitions section (after the state sets) were grouped together
at the end. Now we try to generate stuff in a way that keeps the
relative order the same as in the SNL source.

This approach has limitations: top-level variable declarations must be
generated in one block since in re-entrant mode they all go into a large
struct; there are also auto-generated delarations for SNL function
definitions. Both are now placed (in this order) after all the other
definitions in the initial definition section.

The resulting limitation for literal C code (it cannot refer to global
SNL variables) is the same as it was before. A similar limitation now
applies to SNL functions defined in the initial section (which makes
them less useful when defined there).

The new SNL functions make a lot of embedded C code, especially C
function definitions, obsolete. This means the header file is not as
useful as I thought. On the other hand, function definitions may depend
on stuff that has been declared before. So it becomes more important to
keep the order of definitions in the output as similar as possible to
that in the input file (the variables struct being the most notable
exception). Grouping some stuff in a header file and other stuff in the
C file makes this almost impossible.

This tests that a global SNL variable is (correctly) shadowed by a
function parameter with the same name, even in re-entrant mode.

This change is no more than a one line addition to the lexer spec!

There are three reasons for this move:
- the change in terminology never cought on
- it causes unnecessary naming conflicts, especially now since many more
  things that previously were in escaed C code can now be coded in SNL
- the next version will introduce new and better syntax for this anyway

This came out of the desire to allow function definitions intermixed
with c code and other definitions, and not only at the end of the
program but also in the initial definition section. Some amount of
re-factoring was necessary in the analysis part to make this possible,
since previously we had only one definition list per scope and now the
program has two. More changes were needed in the code generation, mostly
to pick apart the stuff that the parser now mixes together, and also to
beautify the generated code. The separate declarations for function
definitions are no longer in the header file; they are static anyway.

One difference in behaviour is that now the extra escaped C code
sections at the end of a program are paced *before* the state set code.
The advantage is that extra prototypes are no longer needed (except if
the functions call each other resursively). This change should not break
existing programs, since C functions cannot call state set functions. 

Also expanded on the differences between SNL and C syntax and semantics
w.r.t. types and declarations.

This compiler test adds a lot of complicated declarations and type
expressions.

Since .st files are preprocessed with cpp, SNL code may be included. This
patch adds rules to create .st.d files using the mkmf.pl tool from base.
Also removed some obsolete stuff and fixed the CLEANS definition.

Silently changing the meaning of a user program is not nice. Besides,
using the implicit default queue size is deprecated anyway.

This partly a preparation for proper multi-PV array support.