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.

Since we now resolve built-in functions as well as constants during
analysis, we no longer need to access the symbol table in the code
generator. This means we can get rid of an ugly hack. The gen_ss_init
procedure is also no longer needed and has been removed.

The problem was a call seq_monitor(ch, FALSE) inside pvAssign after we
destroy the channel (if one exists). This will always fail (strange I
never noticed that) and as a result dbch->monid would not be reset to
NULL. That in turn means when the channel is re-assigned and connects,
seq_monitor(ch, TRUE) will not do anything because it thinks there is
already a valid subscription.

The fix is to remove the call and instead only reset dbch->monid to NULL.

The function seq_monitor is called by user code via pvMonitor and
pvStopMonitor as well as from the CA connection handler. So we should
make sure that there cannot be a race between the two.

This did not solve the original problem reported by Janez Golob
<janez.golob@cosylab.com>, but it's a valid bugfix nevertheless.

The first removed paragraph was just wrong. The second one proposed
alternatives which I no longer regard as being superior. Connection loss
is not supposed to happen regularly during normal operation, so the
small overhead of waking all state sets is negligable in practice.

We give the hint to use option +p only if the function actually supports
multi-PV arrays. We know this by examining the add_length column in the
builtin function table (functions that support them must add the array
length as implicit argument to the call).