Since we've run into the situation where someone puts a script wrapper around a launcher such as srun, we need to always protect MCA cmd line params with quotes. This means we also need to protect the backend from quotes coming into the system as part of a value, or else the parser gets confused.

So add a new function for wrapping MCA arguments, and tell the backend parser to ignore/remove leading/trailing quotes.

cmr=v1.8.3:reviewer=jsquyres
Improve the --bind-to help message to better indicate the default options under various values of np. Remove the warning message if the user doesn't specify a binding policy and we are overloaded

cmr=v1.8.3:reviewer=jsquyres