Anki add-on: SMART SPACEBAR: automatic ease scoring

This add-on changes what the spacebar or enter key do based on how long it took you to flip the card. So if it takes you too long to respond, spacebar works as Hard or Again. If very quick, spacebar highlights Easy. By default, the times for Easy, Good, and Hard are 2, 5, and 8 seconds respectively. This means, for example, that if you answer in under 2 seconds spacebar will choose Easy, and if over 8 seconds spacebar will choose Again. For new cards, though there is no Hard rating, 8 seconds (Hard rating) is still the threshold for whether spacebar chooses Again. These times can be customized: On Anki 2.0, by editing the few lines of code (Tool>Add-ons>Smart Spacebar>Edit). On Anki 2.1, as above, but the last step is pressing the "View Files" button and then opening "__init__py" instead of "Edit." This may save time (seconds thinking about how to rate a card add up), let you have uninterrupted focus on your cards, and standardize card ratings so they're less subjective. I recommend using this with the add-on Speed Focus Mode, with its "Automatically Show Answer" option set to whatever you make the Hard threshold for this add-on. ======================================================================== COMPATABILITY Tested and working on Anki 2.0 and 2.1 for Mac High Sierra. It doesn't interfere with shortcuts like 1,2,3,4 to rate cards. Works with my other add-on FULLEST SCREEN for Anki 2.1, in case you want to completely hide the bottom toolbar. Known issue: If you scroll down on the card once it's flipped, the spacebar "forgets" and will rate a card as Good. CHANGE LOG 2019-08-07: Add-on created. CREDIT Credit goes to Simcha Rimler for the original add-on "Automatic Scoring" and to Liam Cook for "Quick and Easy" which was the original original. Joseph Yasmeh imported to Anki 2.1 and fixed a bug where new cards had an unexpectedly low threshold for being marked as easy.