Replace lodash with ES6 methods and functions

[stalniy]

This will allow to use native methods in modern browsers and use polyfills for old one. The main benefit is reduced bundle size and -1 dependency.

Update: I can provide a PR if you agree to proceed with this

[radiolips]

I'm so torn. When I updated jquery-ui I got some pushback and I'm still getting pushback from jQuery. ES6 is becoming more ubiquitous of course.

@stalniy I don't want to waste your time, but could you put together a PR? Last time I check for lodash functions, it looked like we were using around 75 of them, and it seemed burdensome to remove. I was initially planning on removing them in favor of Javascript functionality from earlier than ES6.

[stalniy]

@radiolips done

[krilllind]

Doing a quick search inside of the src/gridstack.js gives me abouth 50 hits on lodash.
Functions that are used:

• chain
• sortBy
• isString
• find
• bind
• each
• defaults
• filter
• clone
• without
• map
• reduce
• first
• throttle

Have anyone heard anything new about this? I feel like importing the entire lodash lib for these functions, gives a lot of overhead. Would be grate to get rid of it!

The good thing is that a lot of these functions can be changed into native es6 methods.

[adumesny]

I'm looking at taking this pull request locally as I too need to remove the large dependency on lodash... it's one the biggest lib we are importing now that should be removed. Would be nice to have that taken.