Fixed unnecessary margin on button group buttons

Buttons in groups in bootstrap are styled to touch on inside edges to
appear joined, so should not have a 5 px margin between them.
fix(challenges): challenge csv export now has proper filename

This sets the Content-disposition filename for the Challenge CSV export
to be {challenge_id}.csv.

Fixes #2689.
show mage not wizard in inventory and member modal
wizard to mage in inventory
feat(quests): add flags.levelDrops for dropping items at certain levels
Merge pull request #2701 from deilann/wizardtomage

Change "Wizard" to "Mage" in member modal & inventory
Merge pull request #2693 from colegleason/csv

Set filename when exporting challenge to CSV
fix(quests): quests with a level cap cannot be bought before that level.

Users were buying the vice quest hoping to play it, not realizing it
would drop at that level. Let's restrict buying the quest (at least in
the short term) until you reach that level.

Fixes #2707.
Merge pull request #2610 from etryn/develop

Fixed unnecessary margin on button group buttons
refactor(bs3): sync with develop
refactor(bs3): fix classes modal
refactor(bs3): port rebirth and reroll modals, misc fixes