docs(README): remove xstream readme
docs(README): remove xstream readme

feliciousx-open-source/cyclejs,cyclejs/cyclejs,cyclejs/cyclejs,ntilwalli/cyclejs,cyclejs/cyclejs,feliciousx-open-source/cyclejs,maskinoshita/cyclejs,maskinoshita/cyclejs,staltz/cycle,maskinoshita/cyclejs,staltz/cycle,ntilwalli/cyclejs,cyclejs/cycle-core,feliciousx-open-source/cyclejs,usm4n/cyclejs,usm4n/cyclejs,usm4n/cyclejs,maskinoshita/cyclejs,usm4n/cyclejs,feliciousx-open-source/cyclejs,cyclejs/cycle-core,ntilwalli/cyclejs,cyclejs/cyclejs,ntilwalli/cyclejs