Feature autoreload

Made two changes.

1. Made it possible to manually open/close files. For example if I want to add a break point to a file at a specific line I can now just open the file place a break point then start the debugging process.

2. Added a auto reload feature. It check the opened files every 1000ms and reloads them if the last modification time was altered. I guess a better solution would be to do this on focus of the window but I'm no WinForm expert so I wasn't able to fix that. It would be cool if it was possible to retain the break point locations on reload I guess it would be possible with some diff algorithm comparing the new file contents to the old contents.