Non-zero exit status doesn't pass through.

[simlay]

Looks like if the cargo build (or however it's called) fails, it doesn't cause cargo-bundle to exit with a non-zero exit status.

I changed the example to be non-buildable rust and did:

$ cargo bundle --example hello --target x86_64-apple-ios && echo $?
   Compiling cargo-bundle v0.4.0 (/Users/simlay/projects/cargo-bundle)
error: expected one of `!`, `.`, `::`, `;`, `?`, `{`, `}`, or an operator, found `events_loop`
  --> examples/hello/main.rs:20:5
   |
18 |     aoeu
   |         - expected one of 8 possible tokens
19 |
20 |     events_loop.run(move |event, _, control_flow| {
   |     ^^^^^^^^^^^ unexpected token

warning: unused imports: `ControlFlow`, `Event`, `WindowEvent`
 --> examples/hello/main.rs:4:18
  |
4 |     event_loop::{ControlFlow, EventLoop}, event::{
  |                  ^^^^^^^^^^^
5 |         Event, WindowEvent
  |         ^^^^^  ^^^^^^^^^^^
  |
  = note: `#[warn(unused_imports)]` on by default

error: aborting due to previous error

error: could not compile `cargo-bundle`.

To learn more, run the command again with --verbose.
error: Result of `cargo build` operation was unsuccessful: exit code: 101
0

when it should probably be 101 or something.

[simlay]

Closed in #83.