Items in contenteditable div are sometimes set as next-to-last

[lolgans]

Problem:
Items in contenteditable div are sometimes set as next-to-last, even if the cursor was set at the end.

Reproduce:

• Go to https://ned.im/wdt-emoji-bundle/#apple
• Select the contenteditable div
• Set the cursor to the right end of the line
• Select multiple Emojis
• Notice that your last selected emoji is the next-to-last item in your div

Note:
Seems not to happen for input fields.

Setup:
Google-Chrome Version 60.0.3112.113 (Official Build) Ubuntu 16 (64-Bit)

[needim]

Oh yeah, we should update the caret position after emoji select 👍

[tje3d]

@needim fixed in #45 with better approach