auto completion in buffers

[felixangell]

would be nice to have a little auto complete menu rendered with some keywords/words measured from the buffer?
in addition to this it should be relatively flexible so that we can potentially add our own recommendations, perhaps per language or something?

[felixangell]

tracking:

• arrow up/down selects suggestions if they exist
• pressing enter completes the word from the suggestion box
• handle all little edge cases for the vocabulary stuff
• some kind of thread that will go over a document and load all of the words in the background?
• dont show more than X amount of suggestions/scrolling feature so its fixed in the box menu thing?
• add padding to the items
• set the width of the box accordingly
• add configuration option thingies for colours