JS Backend: made invocation arguments modifieable
JS backend: made JsNameRef name modifieable
JS backend: made JsScope hasOwnName method public
SideEffects
Renaming
Returns
Inlining
use SmartList, since Arrays.asList() returns fixed size list
JS Inline: support inline extension functions
JS Inline: check if expression need to be aliased
JS Inline: default parameter processing for inlined functions

When function is inlined initializers
for default parameters can be:
1. removed  if argument is not `void 0`
2. expanded otherwise
JS Inline: prevent inliner from inlining multiple subexpressions at once
JS Inline: inline local functions
JS Backend: dangerous issues temporary fix
JS Backend: save local and literal functions 'local' status in AST

Reason: to distinguish local functions,
when cleaning up after inline.

Unreferenced local functions can be removed.
JS Inline: identitySet helper function
JS Inline: common reference utilities for cleaning up after inline
JS Inline: remove unused local function instances
JS Inline: remove unused function literals and local functions