Quick reproduction steps:
1. Open attached project "PolyglotUnity"
--- Editor crashes immediately

Alternative reproduction steps:
1. Delete the Library folder from "PolyglotUnity" project
--- This is done so no scene is opened on startup
2. Open project "PolyglotUnity"
3. Open scene "ExampleOptionsScreen"
--- Editor crashes

A way to prevent a crash:
1. Open project "PolyglotUnity" with Unity 5.0 (tested with 5.0.3p3 (70d53b55896f))
2. Open scene "ExampleOptionsScreen"
3. Save the scene
--- This will prevent the crash from happening on other Unity versions

Regression since: Unity 5.0