Fixed query parsing.

[gperdrizet]

Splitting on ';' first and then filtering '--' was resulting in no queries directly preceded by a comment ever running.

For any query preceded by a comment, the result of splitting on ';' would be a block of lines something like this:

-- A comment line
SELECT * FROM observations LIMIT 10;

The '--' filter for comments was then excluding it. This parsing issue was causing the example solution to be non-functional and preventing any queries preceded by a comment from running. The correct approach is to:

1. Split the query document into a line array
2. Remove empty lines
3. Remove comment lines
4. Concatenate the cleaned line array back to a single string
5. Then split on ';' to recover each each individual query as a single line string

Now the commenting system works as intended, and the comment filtering logic is no longer necessary.