iPhone X support, Stock Mail app name & french translation

[nverinaud]

I noticed the following issues regarding the INKMailHandler UI :

• iPhone X support is not good,
• the Stock mail app name is bad (INKMailShe...),
• and there is no french translation.

Here is a screenshot illustrating the issues.

I will do a PR soon to fix this. 😉

[nverinaud]

I cannot manage to make pod install work 😞 I filled an issue on the CocoaPods repo.