new features and bug fixes:

bug fixes:
-	copy() func fix: don't copy a key if it doesn't exist
--		this was resulting in bogus `undef` fields in the output
-	now excluding comments from the search for quoted strings
--		this is important if comments contain apostrophes
--		because they look like the start of a multi-line single-quoted string
new features:
-	added a way to retain any prefix before the JSON on output (`-P`)
-	added a way to read the proglet from a file (`-f`)
-	added a way to print out the Perl code it's going to use (`--debug`)
-	added a new function: stats()
--		this prints statistics for one or more fields
--		statistics include: total lines, total times field was undefined, min value, and max value
-	report for count() now displays percentages of the total
-	made error messages prettier