On my install (Freya) the default key for this functionality is actually Super (meta/windows key). You can change this in dconf-editor by navigating to org.gnome.desktop.wm.preferences and setting mouse-button-modifier to <Alt>
Gala (Window Manager)
The command to respawn the window manager is DISPLAY=:0 gala --replace &.
Note that you ...
This is not really possible without forking the application. Decorations are drawn by the toolkit now instead of by the window manager which means that they are actually part of the application and not something separate.
The program wmctrl allows to you to get infos and change the states of currently open windows. Install it by typing sudo apt-get install wmctrl.
Type wmctrl -l to output a list of currently managed windows:
0x02e00003 -1 username plank
0x02a00003 -1 username wingpanel
0x0340000a 0 username Home: wmctrl
0x0360000a 0 username Scratch
There's no straightforward way to do that, that I know of. Shadows are drawn by the toolkit (Gtk+). You can edit your system stylesheet (located at /usr/share/themes/elementary/gtk-3.0/gtk-widgets.css) and remove the box-shadow from all window-frame classes. But be aware that the box shadow property also effects the inner shadow i.e. highlighting.
You forgot to add some lines of code into the gtk-widgets.css to get the same window-controls. To fix the rest, open up the gtk-widgets.css file in the gtk-3.0 of my theme and search for this:
* Window Controls *
Now Copy everything beneath this comment (including the comment, if you want) and paste it into your ...