Add configuration for disabling search history

[nicokaiser]

After updating to v0.11 there is a new search history feature. While this is really nice, it might be required to completely disable this feature in some cases. In some environments it might not be desirable to save data in localStorage etc.

Setting the histories_count parameter to 0 does not help, since then the default (5) is applied. Setting the parameter to "0" (with quotes!) basically disables the history, but this is more like a hack to the problem.

[razonyang]

Make sense, available since v0.12.0.

params:
  search:
    histories: false

[nicokaiser]

Awesome, thank you!