chore(*): remove unnecessary imports

src/ContextManager.ts

@@ -5,7 +5,6 @@ import {
   ContextAllAttributes
 } from './types'
 import { makeRequest, isUrl } from './utils'
-import { SASViyaApiClient } from './SASViyaApiClient'
 import { prefixMessage } from '@sasjs/utils/error'
 
 export class ContextManager {

src/SASjs.ts

@@ -1,13 +1,3 @@
-import { isIEorEdgeOrOldFirefox } from './utils/isIeOrEdge'
-import * as e6p from 'es6-promise'
-;(e6p as any).polyfill()
-if (isIEorEdgeOrOldFirefox()) {
-  if (window) {
-    window.fetch = undefined as any // ensure the polyfill runs
-  }
-}
-// tslint:disable-next-line
-require('isomorphic-fetch')
 import {
   convertToCSV,
   compareTimestamps,