fix typos in README.md

[nikai3d]

According to the dictionaries available to me, "resize" is the British way of spelling the word, e.g. http://www.macmillandictionary.com/dictionary/british/resize

[thom4parisot]

@nikai3d oh yes, I'll give a look to British spelling rules on the /sing/zing/ thing then :-)

Thank you :+1:

[Integralist]

Just to confirm we respell it resize :-)

[thom4parisot]

@Integralist I asked to colleagues just in case. Google autocomplete (in safe search mode :-p) confirmed it too :-)