for comments - GEOMESA-233 adding scalding job to index attributes through geoserver UI

Still TODO - 
* create ticket for the TODO in the code
* error handling in UI for failed m/r jobs
* unit tests

Ok, lemme see if I know what this does...

It starts with a set of jar names, it checks various paths for that name, and when it finds the file, that filename is added to libjars?

Seems like that could be done with something like
```
for { 
  f <- libjars
  p <- paths 
  if( f+p exists)
yield {f+p}
```