Allow to accept iCode file as input.
Add logic to dispatch parsing based on input type: C vs iCode.
Parser now generates iCode and depends on SDCCicode.h included before SDCCy.h
Add iCode operand type to %union for iCode generation.
Allow to parse raw functional types in iCode mode.
Add getiCodeSym() - return existing iCode symbol or allocate new.

iCode parsing infrastructure.
Add operandFromSymbolSimple (symbol * sym) - create from symbol with no magic.

iCode parsing infrastructure.
Few more declarations for iCode parsing infrastructure.
iCode parsing grammar - WIP.
Changes to minimize diffs on the path C -> (asm, iCode) -> asm.
Add segfault protection for case IC_RESULT (ic) == NULL.

That happens when printing dead-code eliminated ic for example.
Add support for defining vars to iCode.
Store defvars in a separate iCode chain.

There were codegeneration artifacts when storing them on common chain.
To not go and add checks throughout the code, just store on a separate
chain.
Comment out few more boring flags.
Reset SymbolTab after each iCode function is processed.
Make sure that .globl is output for function.