fix tenses
small updates to spelling, double space removal
* fix "'s" spelling for ISAs
* fix comas
* add definite/indefinite article where needed
* fix verb forms (have/has, work/works)
comment on lisp machines/more complex cpus
* fix comas
* add definite/indefinite article where needed
* fix tenses
add note on branch delay slot explanation
fix definitive article, other small things, small styling fixes
fix definitive article, other small things, small styling fixes