Usability fixes

A couple of things that could make this tool more usable. I'm using windows 10, and configuring for an ergodox infinity on the 1.0.0 windows .exe and .zip release. These are little frustrations and nit-picks that I encountered with the UI while trying to figure out why my ergodox wasn't flashing properly.

Allow for opening of .json files in the import keymap popup. This could be easily added by an "open" button. Along those same lines, allow for drag/drop of json files onto this window.

Allow the header data in advanced settings to be edited. Currently, I can't see a way to change the names/variants/layouts/etc... other than copy/pasting the json, and editing it manually before importing.

Allow us to save the layout to a .json file directly. Either via the "view raw json" button, or a file menu. Copy/pasting from the "view raw json" button is an extra step that we shouldn't need to do.

In the flash window, hitting the "open file" buttons take you to a completely different folder than the files listed in the "dfu-util command" and ".bin to flash". This is especially noticeable if you tried flashing from a custom location. Also both buttons take you to the same incorrect folder.

I should be able to drag/drop files onto the filepath boxes in the flash window to populate them.

From the quick flash, the flashing progress log isn't saved anywhere I can find, and it's not on screen long enough for me to see if there are any issues, or just general debug information before the page is changed. Don't change the page. This is also an issue for the left/right flash for the ergodox.

Allow for downloading the firmware to a custom location, or with a custom name, perhaps via a right-click menu on the download button.

The JSON files in the firmware cache should have the same formatting as the raw json, that way users can easily diff their files. (If that was done to make the files smaller to transfer, when the file is recieved, it should be formatted)

The home page should let you click on the picture of the keyboard you have, or the picture should be changed. I tried clicking the pictures before noticing the buttons on the left.

That's all for now!