Added FileTree auto refresh and open files auto refresh when modified out of editor
When the current session is closed, the previous one is restored
The close button is bigger, the tabs do not resize on hover, and middle click close them
Compiled main.js with last changes
When the FileTree is refreshed, the previously open folders are still open
Merge pull request #43 from cybrown/dev

FileTree and open files auto refresh, reopen last file if current file is closed, better UI for tabs.