update scala native version

[joprice]

Hi I'm interested in this project but hit a few bits of coderot when trying it out and haven't yet gotten it to run an app successfully. A few issues I hit:

• some new facilities in scala native need extra guards to avoid or allow compilation on ios: https://github.com/scala-native/scala-native/compare/0.4.x...joprice:scala-native:supportIOS?expand=1
• unpublished objc helper lib - luckily the source jar was available and I temporarily checked it in here
• some restructuring of unsafe and unsigned libs in scala native caused some imports to be change
• it seems some of the files were codegen'ed, but not sure what command was used. it would be great to try to rerun that and maybe contribute fixes to the codegen to support ios/objc
• the generated selectors for setters include invalid characters that will need to be sanitized: "Names of vals or vars may not end in _="