[objcgen] Capture the inner exception for handled NotImplementedExceptions. (#307)
[objcgen] Capture the inner exception for handled NotImplementedExceptions. (#307)

This makes sure that we can print the original stack trace, which makes
finding out what wasn't implemented easier.
mono/Embeddinator-4000,jonathanpeppers/Embeddinator-4000,mono/Embeddinator-4000,mono/Embeddinator-4000,mono/Embeddinator-4000,mono/Embeddinator-4000,jonathanpeppers/Embeddinator-4000,jonathanpeppers/Embeddinator-4000,mono/Embeddinator-4000,jonathanpeppers/Embeddinator-4000,jonathanpeppers/Embeddinator-4000,mono/Embeddinator-4000,jonathanpeppers/Embeddinator-4000,jonathanpeppers/Embeddinator-4000