fix/clarify msa constructor 
fix/clarify msa constructor 

I think the ```require``` in these examples could do with an explanation. Most people will start out by just linking to the CDN, and will wonder why ```require``` isn't available. If, later on, they do use require, they may also wonder why ```new msa()``` doesn't work (apparently this needs to be ```new msa.msa()```)

Former-commit-id: abc456fa0302a45307e038e14e84aa85ffdf31d6 [formerly 64671972c2a03aa2c88b86d7f3f4e6ded50b24a6]
Former-commit-id: 6fcd35b8184fca499980381ba437e0c96165a791
greenify/msa,greenify/msa,greenify/msa