Rename Js::RKellyParser to Js::Parser.

So we don't have to change all the tests that target the old Js::Parser.
Besides, it's better to use a more generic name anyway.
Fix adapting of DoWhileNode.

The "test" and "body" parts had been switched.
Fix adapting of LogicalExpressions.

Previously && and || were treated as BinaryExpressions, but Esprima
classified these as LogicalExpressions.
Fix string detection in Js::Returns.

Because the EsprimaAdapter gives a string value to regex literals,
which is different from nil received from Esprima itself, we'll
have to check first for regex and after that for string.
Fix up Serializer spec.

It still referenced the old Esprima engine.
Eliminate test for let expression.

That's not supported by RKelly, and really not needed in practice.
Add required variable to catch statement test.

Missing variable in catch clause is a JS syntax error.
This happened to work in old Esprima, but no more works in
neither new Esprima nor RKelly.
Fix adapting of ForInStatement.

When for-in contains variable declaration, Esprima produced the
whole VariableDeclaration, but RKelly gives just VarDeclNode -
so we wrap it inside a VariabelDeclaration to match Esprima output.
Up the rkelly-remix dependency to 0.0.2.

Use the ~> syntax to allow us to release patches to rkelly-remix
and get the picked up by jsduck installations.
Up version to 5.0.0.beta5