Amalgamate the electron build packaging into one script.
Use update_base_url so we can compute the actual URL in the
script for windows (because we need to put it in the build) and
at runtime for mac os.
* Remove squirrel hooks (the installing & uninstalling is now
done by the, er, installer)
* Switch to electron-auto-update
* Shorten initial update delay because we no longer need to wait
for squirrel to release a lock file
* Change update URLs because windows is now one installer for
both 32 & 64 bit.
* Update electron-builder to 10 where NSIS is now the default
target for Windows.
* Add linux to the target list, building a deb.
* Remove sqirrel-specific installation spinner
* Remove redundant !**/* from files
Otherwise everyone that builds electron vector will end up with
their apps auto-updatin to our version when we release an update.
Coming next: A way to manage our electron release process to make
sure we never ship a build with auto-update disabled.
* Implement the squirrel install / uninstall hooks (so we have
a start menu entry / desktop shortcut)
* Wait longer before checking for update
* Set the window icon
* Add a 'file' menu
* Bump electron-builder
* Add the icon url for the control panel entry
