explicit package creation

It's hard to inject right transport type, default namespace etc.
into implicitly created package.
If it is created explicitly, it helps requirejs implementation.
error handling extracted, nicer code

also fixes mysterious errors when errors handling disappears
after first error in handleError; now finally gets to work in any case
No need for this. with createHandler
wireKlass inlined, now that was only used at one place
.meta = true shared for all metaclasses
Object.create(null) so hasOwnProperty can be ditched
Fixes #574
Merge pull request #608 from herby/explicit-package-creation

explicit package creation
Merge pull request #609 from herby/boot-js-refactorings

Boot js refactorings
Merge pull request #613 from herby/gh-574

Fixes #574
Merge branch 'master' into requirejs