Fixed bug in ElectronLocation.cc

The function inAcceptance didn't have breaks in the case statement. I
incorrectly concluded I didn't need them because we had if statements,
but not including them caused some cases to drop through until they were
true, and then return true incorrectly.

I've also expanded the lines, there is no reason to try to keep the
function compact in lines.
Adding testing function for ElectronLocation.

Added testElectronLocation.cc to test that inAcceptance returns the
right answer for the various locations and a selection of etas.

Also added the function electronLocationToString to convert the enum to
a string for human reading.