add all local packages to common externals

[giladgray]

addresses #2306, fixes #1805

so they never get bundled in each other.
also use "expanded" externals syntax so the correct name is used for each module system.

[blueprint-bot]

add all local packages to common externals so they never get bundled in each other

Preview: documentation | landing | table

[giladgray]

webpack UMD header now looks like this:

"object" == typeof exports && "object" == typeof module 
    ? module.exports = t(require("react"), require("classnames"), require("react-dom"), require("dom4"), require("react-transition-group"), require("@blueprintjs/icons")) 
    : "function" == typeof define && define.amd 
        ? define(["react", "classnames", "react-dom", "dom4", "react-transition-group", "@blueprintjs/icons"], t) 
            : "object" == typeof exports 
                ? exports.Core = t(require("react"), require("classnames"), require("react-dom"), require("dom4"), require("react-transition-group"), require("@blueprintjs/icons")) 
                : (e.Blueprint = e.Blueprint || {}, e.Blueprint.Core = t(e.React, e.classNames, e.ReactDOM, e.window, e.ReactTransitionGroup, e.Blueprint.Icons))

[blueprint-bot]

use expanded externals syntax

Preview: documentation | landing | table

[blueprint-bot]

whitespace

Preview: documentation | landing | table