small fixes and new props

[bgadrian]

• added ignore for .idea;
• fixed css missing spaces tag title; (when a tag had spaces "no mine", and if the search term was "no" or "mi" the space dissapeared.
• added prop to add custom classes to main input;
• added addNew optional property for each category; I made a "custom keywords" category and let the user only add there, this way the "add new ..." will noe appear 10 times if you have 10 categories.
• removed duplicate field from README
• added prop inputAutoSize to control the size attribute of the main input ; if the size is controlled with CSS example bootstrap, using the "size" mess the layout.

[bgadrian]

I've done the changes you ask, and by mistake I pushed a new feature, I hope is ok https://github.com/erizocosmico/react-categorized-tag-input/pull/22/commits/8f8789bfb723e51272d9360eb6f97114ee5b05bb

It was weird as in the user sees "Fruits" category but can't see all the fruits available, Instead of making a helper page to list all the tags, the search itself can be be used to discover what tags are available. I have over 100 tags so it's a real problem for me.

[erizocosmico]

:+1: for the changes.

About the new feature, I think it's okay, but I'd rather have it display all the category tags only if there is no tag that matches the input. Otherwise, if the category has the same name as a tag, it's difficult to select that tag.

[bgadrian]

Makes more sense to show all of them by default, trough sometimes will require a scroll. I do not know how to remove a commit from the pull request though. The chance that a category has the same title as a tag is kinda low if I think about it.

I made other small features too, if this works maybe I'll make another push request next week. Example to change the minimum input length (now is hard coded 1).