Remove micro-optimizations for better minfiication

[LeaVerou]

Currently the code has a number of optimizations to minify better, which sometimes get in the way of readability, e.g. local single letter variables for true, overly long variable declarations with dozens of variables instead of separate ones and things like that.

These may have made sense in 2012 when jsep was first written, but in 2021, I think saving a few bytes at the expense of readability isn't worth it. Especially for a codebase as small as jsep, where the savings are not that huge anyway.

@EricSmekens are you ok with me refactoring these out slowly in the cases where readability would be improved?

[EricSmekens]

I completely agree. I think there are more optimizations possible when the code is more simple, so I fully agree on that fact.