added default module path inside init function when target is web

[ibaryshnikov]

Closes #1559

[alexcrichton]

Does import.meta work in all browsers today that support import? It sounded like on chat it was a somewhat experimental feature, so while it's fine to support we may want to hold off on changing default examples until it's supported everywhere.

[Pauan]

@alexcrichton It doesn't work on Edge (I tested it), but it works on all other modern browsers.

It obviously won't work in IE or older browsers, but maybe Webpack can help polyfill import.meta?

[Pauan]

(Also, it's stage 3 in TC39, so it's unlikely to change at this point)

There's also some discussion about Webpack polyfilling it.

[alexcrichton]

Ok nice! I think in that case this is probably fine to go ahead and land and switch the defaults. FWIW this probably won't benefit much though from a webpack polyfill because this is the --target web target whereas the default bundler target already doesn't have to deal with this and webpack takes care of it!

Thanks @ibaryshnikov and @Pauan!