Add CmdOrCtrl+Shift+W shortcut to close log file

[ianleeder]

I'm often switching between mutliple log files, and wanted a more convenient way to do so. That's the original reason I downloaded the source code!

Many apps accept Ctrl-W to close the current document. That's already in use to close the window, so I added Ctrl-Shift-W.

[ianleeder]

Also, this is just a poor-man's workaround. What I really wanted was to simply drag-n-drop over an existing log, and open a new file. But I'm not familiar enough with Angular or the dropzone library, and this was a quicker fix.

[warrenbuckley]

Code change looks fine to add this new keyboard shortcut Thanks @ianleeder

[warrenbuckley]

Looks good to me, thanks @ianleeder