Bug/Enhancement for https://github.com/greenmanspirit/journal.txt/issues/14

Added global utility function to query the user and loop until a valid answer is given. I then replaced all previous queries with this function. I believe this is safer than what I was doing and assuming answers if a non-default answer is given.
Bug/Enhancement for https://github.com/greenmanspirit/journal.txt/issues/17

This was fairly simple. Instead of usign the || assignment, I test for false from find_entry and notify the user that there is not entry and then exit.
Added a comment that I missed before
Bug/Enhancement for https://github.com/greenmanspirit/journal.txt/issues/11

Even though https://github.com/greenmanspirit/journal.txt/issues/17 was added later, this fix was a lot easier after doing 17. Part of solving this was to make all date variables date objects. This gave me the ability to use '<' to test when we passed the date we want. As a result I had to tweak a few things to get the date objects working right in place of date strings. I have a feeling this will help down the line with adding date formats.
Fixed quotes to be consistent