Log yet better errors from testSynclet.js

Error objects don't respond usefully to `JSON.stringify` - they just become
`{}` - so now I'm testing the string representation against `[object Object]`
and only then stringifying it. This way, strings stay strings, objects get
printed, and errors do their own special thing.

This is sad. Is there a better way?
Support sandboxed synclets in testSynclet

Sandboxed synclet configs aren't compatible with unsandboxed ones because of the
namespacing that happens, so they would either run from a blank slate every
time, or bail in the event that they needed the `all` config section to
communicate. Now we check whether the synclets are sandboxed and wiggle the
config into the right shape.

The returned `pi` that we use to support paging needs to do the merging that
happens in the real world, because synclets don't always hand back their full
config object - only updates. We're not quite doing that yet, but none of the
synclets I've been testing have cared, so I'm putting it off. Setting `pi =
data` is almost certainly totally wrong because it throws out the `auth` object,
but that's how it was and I don't have a use case to fix it yet.

Really what needs to happen is that we refactor `taskman` so that we don't have
to redo so much of this work. This parallel harness is only getting larger and
has already started to diverge.
Lint profileManager

No need to type all these silly characters.