Improved swear_word_counter and plotting

swear_word_counter.py:
- You can not gather data from the same subreddit twice. You have to
rename/delete/remove the already existing csv file if you want to
gather other data from the same subreddit.
- The subreddits will append to a new line in the csv file so you can
analyze more data from different subreddits.

datafile_plotting.py:
- Boxplot integration
- Bar plot integration
- Scatter plot integration