CQL code comments

Add comments to CQL code.

Use the following notation to include comments in CQL code:

For a single line or end of line put a double hyphen before the text, this comments out the rest of the line:
```
select * from cycling.route; -- End of line comment
```
For a single line or end of line put a double forward slash before the text, this comments out the rest of the line:
```
select * from cycling.route; // End of line comment
```
For a block of comments put a forward slash asterisk at the beginning of the comment and then asterisk forward slash at the end.
```
/* This is the first line of 
   of a comment that spans multiple
  lines */
select * from cycling.route;
```