saving: add a simple mechanism to download files
saving: add a simple mechanism to download files

This adds basic support for downloading files.

A separate patch will be submitted to support uploading of files.

Signed-off-by: Sean Cross <d7e19930cc1f42c2d0781f4d9e6f1fe5891bf9cf@xobs.io>

chibitronics/ltc-webview-layer,chibitronics/ltc-webview-layer,chibitronics/ltc-webview-layer,chibitronics/ltc-webview-layer