fix bugs on homepage when no sketches exist in db; refactored methods from view to model
fix merge conflicts in consultation with Lydia
reverse latest list so the most recent sketch appears at the top

also increase the home page limits to 8 popular trees and 10 recent sketches
Merge pull request #58 from jsum528/SRB/home_page_fixes

Srb/home page fixes
Merge branch 'master' into LJK/buttons
added lineage pictures next to the sketch in sketches#new
added active inset shadow for buttons
Merge pull request #59 from jsum528/JS/new_sketch

added lineage pictures next to the sketch in sketches#new
changed nav links to buttons, fixed centering issues
Merge branch 'master' into LJK/buttons