reimplementation using bash arrays

Hi,

I've spent far too many hours on this, but I think it finally does what I need it for...
And this pull is for you to consider if you like it, otherwise just drop it ;)

There's still some quirks to work out, more tests to write etc... and I'll probably do some of it (as I intend to actually use this).

The tests should run fine, the delete test has been skipped, as I don't support modifications to parsed json objects at the moment.