Make the app work out of the box - dependency and bug fixes

[king-millez]

This pull request fixes a plethora of issues:

• Saving the config no longer throws an error
• Writing to the DB no longer throws an error
• Dependency versions are now set with requirements.txt
• The get_user function now uses user_id as a *kwarg instead of just a raw arg
• Tweepy exceptions updated
• Timezone comparison will now work by converting all datetime objects to UTC standardised datetime objects
• Opening files with emojis or other unicode characters will no longer crash the app

Please note

I did these fixes to make Semiphemeral work to unlike Tweets on my account. I haven't tested this with the other modes (except configure) and I'm not sure if they even work. This is however at least a start and should allow the application to work from an initial clone and not immediately fail like it currently does.

I would suggest those coming from #113 and #121 to use this branch.

[king-millez]

@pdelteil perhaps #107 and #108 can be merged to this branch instead so there is a consistent "up to date" branch for Semiphemeral which actually works?

[dideler]

For others coming across this wondering whether there's a good fork to use, these are the most ahead with patches.

• https://github.com/king-millez/semiphemeral
• diff: https://github.com/micahflee/semiphemeral/compare/master...king-millez:semiphemeral:master  
• https://github.com/IronKyle38/semiphemeral
• diff: https://github.com/micahflee/semiphemeral/compare/master...IronKyle38:semiphemeral:master

Haven't tried either yet.