Implement LAMBDA and LAMBDAP

[GillesDuvert]

3 differences with IDL's LAMBDAS:

1. lambda text must always be a string (between " "). Needs a change in the ANTLR compiler to do otherwise.
2. lambdas are here but their use is limited since GDL variables are not yet objects that would know about the MAP, REDUCE and FILTER methods.
3. Using a lambda in QROMB() needs to have defined it before:

GDL> compile_opt idl2
GDL> result = QROMB("LAMBDA(x:x^3 + (x-1)^2 + 3)", -4, 4)
% Function not found: LAMBDA(X:X^3 + (X-1)^2 + 3)
% Execution halted at: $MAIN$          
GDL> zzz=LAMBDA("x:x^3 + (x-1)^2 + 3")
GDL> result = QROMB(zzz, -4, 4)
GDL> result
       74.666664

Obviously having lambdas more inlined, thus changing the Parser, would be great.

[alaingdl]

This is really smart, and I can compile it with gcc 8, but I can NOT compile with gcc 11, due to object.cpp

31%] Building CXX object src/CMakeFiles/gdl.dir/objects.cpp.o
/home/coulais/GDL/gdl-1.1.3git260123CMake/src/objects.cpp: In function ‘int ProIx(const string&)’:
/home/coulais/GDL/gdl-1.1.3git260123CMake/src/objects.cpp:1048:48: error: incomplete type ‘DInterpreter’ used in nested name specifier
1048 | EnvT* requestedScope = (EnvT*) DInterpreter::CallStackBack();
| ^~~~~~~~~~~~~
/home/coulais/GDL/gdl-1.1.3git260123CMake/src/objects.cpp: In function ‘int FunIx(const string&)’:
/home/coulais/GDL/gdl-1.1.3git260123CMake/src/objects.cpp:1071:50: error: incomplete type ‘DInterpreter’ used in nested name specifier
1071 | EnvT* requestedScope = (EnvT*) DInterpreter::CallStackBack();