Adding detection of multiple boards at once

Multiple boardConfigs are stored in the vector 'boardConfigs', to add a config use .addBoardConf(string filepath).

The changes aren't as big as the line numbers say, I maybe did some strange formatting... Basically I used the concept of markers for the boards as well, by moving everything to a vector of boards and creating the appropriate methods. There's no way to remove a specific board though. Also the example isn't updated yet (but still works since the api is "backwards-compatible").