Manual Port & Baud Selection

[StaticRocket]

Proposing drop-up list for open ports next to the board selection drop-up list. Could be potentially helpful for troubleshooting errors like #24 and allow for multiple connected boards without upload issues. It would also help to be able to toggle the baud rate of the serial monitor within the monitor tab.

Upon further investigation it appears that arduino-upload/styles/arduino-upload.less has multiple instances referring to a serial selection button. Is this actually implemented and I'm just blind, is this a bug, or was that a the remains of a WIP from a while back? I'm doing some digging to see if I can get it working but you'll have to forgive me, this is my first attempt at decrypting CoffeeScript and Less.