bitfloor module missing in parent pom

mvn clean package doesn't work since the bitfloor module is not added to the parent pom.

Error was:

>[ERROR] Failed to execute goal on project xchange-examples: Could not resolve  dependencies for project com.xeiam.xchange:xchange-examples:jar:develop-SNAPSHOT: Could not find artifact com.xeiam.xchange:xchange-bitfloor:jar:develop-SNAPSHOT -> [Help 1]