Fix bug: correctly generate code when accessing external variables declared inside FBs as a structured variable (realvar := fb1.fb2.extvar1.realvar)

Fix bug in standard: standard does not allow multiple VAR_GLOBAL ... END_VAR constructs in configurations and resources. This is probably a bug, so we allow it.

Code cleanup (part 3): generate_c_typedecl_c is no longer needed for code generation in POUS.c It is now only needed for datatype declaration in POUS.h

Code cleanup (part 2): generate_typedecl_c now only prints to POUS.h !

Code cleanup (part 1): subrange check functions are now declared in POUS.h (as static inline functions or #define)

Fix get_datatype_info_c::is_subrange(), which did not work when using base type! (we now use get_equivtype() instead of get_base_type() )

fix a couple of typos.

Fix bug - correctly declare struct members whose type is a directly defined array (e.g.: STRUCT x: ARRAY of XXX; END_STRUCT)

Start using the called_fb_declaration annotation when generating C code from FB calls in ST.

Code cleanup: move datatype analysis to get_datatype_info_c

Fix bug-fix of previous commit.

Fix bug: allow use, as lvalues, structures/arrays inside FBs (e.g. fb1.struct1.r := 33.3).

Fix bug/issue #33 (correctly access struct/array variables declared inside a FB -> r:=FB1.FB2.struct1.array1[3] )

Add assertion suggested by Manuele.

merge

Use get_datatype_info_c::is_type_valid() to determine datatype validity
(some datatype bugs in source code were going unreported!)

Recursively check the datatype compatibility of values/expressions passed in function/FB invocations.

Change error message text so as to become more suitable to where they might occur in the source code.

Add code to check if an IN_OUT variable is being passed an IL list in formal IL FB/function invocations.

Generate correct error message when encountering IL lists embedded in IL formal invocations.

Fill in the 'datatype' anotation in the identifiers of symbolic variables.
(even though currently it is not being used).

Fix C code generation of FB invocation in IL.

Fix detection of datatype errors on IL conditional flow control operators (JMPC, RETC, ...)

Allow array_dimension_iterator to accept an array_spec_init_c.
Fixes bug activated by generating C code from IL code containing array variables.

Small code cleanup (move common code to a function)

Fix datatype analysis of conditional IL operators (CALC, CALCN, RETC, RETCN, JMPC, JMPCN, S and R)

Fix datatype analyses of S and R IL operators.

make sure all IL operands are narrowed (datatype checking algorithm)

cosmetic change only - fix code alignment.

Add support for FB call semantics of 'S' and 'R' IL operators!
Remove segfaults when analysing buggy IL code (IL operators with no operands).