Change "Zotero Standalone" references on Windows to "Zotero"

[dstillman]

Installer text, install location, icon captions (Start menu, Desktop), uninstall entry…

For upgraders, we'd want to uninstall from "C:\Program Files (…)\Zotero Standalone" first, assuming that's possible.

[dstillman]

If we change references in the installer, we can maybe uninstall with http://nsis.sourceforge.net/Auto-uninstall_old_before_installing_new to avoid trying to rename everything on the system.

I'm not sure what we can do about people updating in-app.

[dstillman]

OK, after 199a389, new installs on Windows are now "Zotero" (desktop shortcut, program directory, etc.), reinstalls become "Zotero", and uninstalls after an in-app upgrade to 5.0 will properly delete the full program directory and not leave files behind. In-app upgrades will remain as "Zotero Standalone", because I really don't want to try to figure out how to change that, but if you reinstall it will become "Zotero". And the program itself has always shown "Zotero" in the title bar.