Initial attempt to remove website addresses from comments.
This is probably not the best solution, but it seems to be working and will perhaps be reworked in future to improve removing website addresses. This closes #7.

Also disables code to underline spelling mistakes since it is still experimental.
At last added an icon for the options page.
Added "Feeling Lukcy" action for misspelled words. This option replaces the misspelled word with the first spelling mistake in the list of spelling mistakes. This is very useful in the event where there is only one suggestion and it is the correct word.
This closes #13