Some upgrades

[justastranger]

• I moved the stack height input to the left, extracting its associated value from the reactor layout class and treated it equivalent to the config values so that you could update it without clearing the reactor layout
• Added an export and import mechanism based on stringifying the reactorLayout variable and encoding that as base64, then importing it by decoding it into a JSON object and replacing reactorLayout's properties with the tmp JSON's and then updating the table