Don't use this library unless linking error is resolved

Hi all! I'd like to warn you that you shouldn't use this library unless there is some fix for the linking error. I just spent almost 30 minutes on tweaking some hero transition just to realize that you won't be able to build the solution at all.

```
clang : error : linker command failed with exit code 1 (use -v to see invocation)
MTOUCH : error MT5211: Native linking failed, undefined Objective-C class: Hero. The symbol '_OBJC_CLASS_$_Hero' could not be found in any of the libraries or frameworks linked with your application.
MTOUCH : error MT5201: Native linking failed. Please review the build log and the user flags provided to gcc: -Xlinker -sectcreate -Xlinker __TEXT -Xlinker __entitlements -Xlinker /Users/dominik/Leancode/gastrojob-mobile/src/Project.iOS/obj/iPhoneSimulator/Debug/device-builds/iphone9.1-12.0/Entitlements.xcent
MTOUCH : error MT5202: Native linking failed. Please review the build log.
```