support for table, multiple irules and multiple events

I changed `event` to `trigger` as `event` is used by iRules(tm), I think it's also more common to have the method called `trigger`.

You can now trigger multiple events and see what state you mock table is in:

```tcl
trigger CLIENT_ACCEPTED
trigger CLIENT_ACCEPTED

verify "foo" 2 eq { table keys -subtable "foo" -count }
```

The table implementation is very naive it only works for this case.

See `test/test_table.tcl` for an example on how this works.

Some tests are still having trouble but i'm not sure what is wrong with them and I have only tested with `tclsh`.