Export the ability to get the start and end addresses for functions

and symbols, and also allow clients to get the prologue size in bytes:

    SBAddress
    SBFunction::GetStartAddress ();
    
    SBAddress
    SBFunction::GetEndAddress ();
    
    uint32_t
    SBFunction::GetPrologueByteSize ();

    SBAddress
    SBSymbol::GetStartAddress ();
    
    SBAddress
    SBSymbol::GetEndAddress ();
    
    uint32_t
    SBSymbol::GetPrologueByteSize ();

llvm-svn: 126892