Include isr into main zinc rlib

[bharrisau]

There are some issues with symbols going missing on OSX during linking (#41). Investigate and fix.

• find source
• submit fix
• remove symbol stripping from Rakefile

[teachop]

If you need testers I can help. As of this AM it is now building on OS X without the symbol undefined error. Thanks.

[errordeveloper]

I was actually wondering why we have separate crate for this... I'm happy to help fixing this.

[farcaller]

so we need to have pub use in the app crate for that, right? That should be doable, especially if PT does that implicitly for the user.

[mcoffin]

It turns out that this is due to using the system ar on OS X instead of the one that comes with the toolchain. autotools now detects the right AR and puts it in .cargo/config. Therefore, this was fixed with the landing of #285.