Add new default and Join pictures

Dope pictures from 2017 CFCs!
Signed-off-by: Ethan Madison <ethan@ethanmad.com>

config.toml

@@ -7,7 +7,7 @@ copyright = "(c) 2017 University of Michigan Fencing Club"
 [params]
   noCategoryLink = true
   description = "Back-to-back USACFC champions!"
-  image = "img/2016cfcawards.jpg"
+  image = "img/2017_CFC_team_with_trophies.png"
   themeColor = "#003e78"
 
   # Google Calendar ID used to embed agenda in sidebar.

content/join.md

@@ -4,7 +4,7 @@ date = "2016-06-28T14:00:17-07:00"
 tags = ["document"]
 title = "Join"
 noshowdate = true
-image = "../img/mfoilwin2016.jpg"
+image = "../img/2017_CFC_huddle.png"
 +++
 
 No experience is necessary, and all equipment is provided by the team!