Changes

# <s>'''Function calls'''</s>## <s>What: Ability to call other Ion or interpreter JS functions</s>## <s>Dependencies: Bailouts, maybe ICs?</s>## <s>Work involved:</s>### <s>Handle monomorphic versus polymorphic calls (ICs).</s>### <s>Handle arity mismatches.</s>### <s>Modify trampolines and calling convention so frame reconstruction can restore nested frames.</s>## <s>Priority: High</s>## <s>Time: 4+ weeks</s>## <s>Status: <b>Done, except for TI intergration.</b></s>## <s><b>Owner: sstangl</b></s>