Fix style consistency errors, minify code better

Gets rid of useless variables and makes basic code structure changes for better minifying. Also fixes some whitespace stuff.

**Changes:**
- Create `Array.prototype.slice` reference
  - `var args = Array.prototype.slice.call(arguments, 2);`
  - `var args = slice.call(arguments, 2);`

- Replace callback/constants creation with function
  - `_.isFunction(callback) ? callback : _.constant(callback);`
  - `makeCallback(callback);`

- Removes variables that are only used once
  - `var cb = handler.callback, context = handler.context; cb.apply(handler.context, args)`
  - `handler.callback.apply(handler.context, args)`

- use expressions instead of if statement blocks
  - `if (!this._requests) { this._requests = {}; }`
  - `this._requests || (this._requests = {});`

- use named functions instead of variables
  - `var name = function() { ... }`
  - `function name() { ... }`

- use shorthands
  - `var isChannel = this._channelName ? true : false;`
  - `var isChannel = !!this._channelName;`

- Fixes misc whitespace weirdness