Closes #340, Change isInstitution to fieldMode everywhere

Including in the DB, which it turns out isn't really all that bad (thanks, among other things, to SQLite's ability to DROP tables within transactions without autocommitting (which MySQL can't do))

userdata.sql

@@ -1,4 +1,4 @@
--- 5
+-- 6
 
 -- This file creates tables containing user-specific data -- any changes
 -- to existing tables made here must be mirrored in transition steps in
@@ -131,7 +131,7 @@ CREATE TABLE IF NOT EXISTS creators (
     creatorID INT,
     firstName TEXT,
     lastName TEXT,
-    isInstitution INT,
+    fieldMode INT,
     PRIMARY KEY (creatorID)
 );