Added logo for Compe Center
Added Gemlock Lock File to .gitignore
Remove HTML fragments for "DELETE" entries from approvedSignatories.md file
Added contributors from Maceio, Alagoas, Brasil

Taina de Ribeiro
Diogo de Carvalho
Dieges da Silva
Iago de Barboza
Camilo de Campos
Gustavo Costa
Tiago de Andrade
Leandro de Sales
Merge pull request #123 from pelegri/master

Sync with latest Jekyll and contributors from Maceio