Add additional separator keys for tag creation

[shalanah]

What this does

Allows more keys to create tags than just enter key. It is an optional prop called separatorKeys which is an array of numbers. I'm excited to use it on commas, spaces, and tabs.

[shalanah]

PR probably not needed if either of these other PRs are accepted: #15 ... looks like a lot of us are into tabs, spaces, and commas!

[shalanah]

This PR also adds a small amount of code to apply text on blur to tags (useful for mobile)

[kunhokimcareerday]

I want this feature 👍

[shalanah]

@kunhokimcareerday Not sure if there will be any movement on this but you can dupe my branch if you want or use it for the time being. I'm using in my package for now "@pathofdev/react-tag-input": "https://github.com/shalanah/react-tag-input.git#master"

[kunhokimcareerday]

@shalanah Thanks I think I can fork yours :)

[alexanderl19]

If anyone stumbles onto this PR in the future, https://github.com/yairEO/tagify seems to be a well maintained alternative. I haven't had the opportunity to test it out extensively yet, but it seems like it has all the features of this library and some (including the one this PR adds).

[kunhokimcareerday]

@alexanderl19 Thx it looks awesome