Minor updates to executor.rb
Minor updates to executor.rb

- Every option should have a short version.
- Named the Engine object 'engine' because consistency.

BinLee/nagios-herald,etsy/nagios-herald,etsy/nagios-herald,kenzophuong/nagios-herald-1,etsy/nagios-herald,kenzophuong/nagios-herald-1,BinLee/nagios-herald,etsy/nagios-herald,kenzophuong/nagios-herald-1,kenzophuong/nagios-herald-1,BinLee/nagios-herald,BinLee/nagios-herald