Merge pull request #115 from Turbo87/friend-tracking

Tracking: Show friends in additional list on top
Use mock lib to patch db.session.commit

Otherwise, original function will not be restored if any of assertion
fail.
Separate cleaning and bootstrapping test db.

This will allow generic model tests to pass (they expect totally empty
database)
@reify decorator added (ported from pyramid)
Simple achievement detection
Model for unlocked achievements
Correct achievement data extraction
Do not fail to repr flight if no id was yet assigned
Unlocking achievements on track upload
Index name for UnlockedAchievement
Stricter database contstraints for UnlockedAchievement
Missing > added to UnlockedAchievement repr()
Use set for achievement lookup

This should make achievement detection a little bit more optimal
Do not show acievements after flight upload

Detailed flight analysis might be not available at that moment.
DB schema update for storing achievements
Create notification when achievement is unlocked
Unlock achievement after detailed flight analysis
Achievement notification UI
Notification icon for achievement events
fixup! DB schema update for storing achievements