Supporting inputs in ie8 — workaround for the missing oninput event

One example of a problem this fixes is
* you call setValue with some value
* edit the input manually
* call setValue with the previous value again
* nothing changes, since [this][valueChangeComparison] check fails because [oninput][oninput] never fired

[valueChangeComparison]: https://github.com/yandex-ui/nanoislands/blob/30eb0cb182772f13a999be23145b743e9aca94c5/blocks/input/input.js#L291
[oninput]: https://github.com/yandex-ui/nanoislands/blob/30eb0cb182772f13a999be23145b743e9aca94c5/blocks/input/input.js#L46