Enhancement: update reducers for team creation, deletion, and modification.

[NathanWEdwards]

When a user creates, deletes, or modifies a team, changes may not immediately appear on the Home and Leaderboard screens.

The teams and profile reducers should handle SAVE_TEAM_SUCCESS and DELETE_TEAM_SUCCESS to update state.teams.teams.

Teams Reducers

• CREATE_TEAM_SUCCESS adds a new team to state.team.teams
• DELETE_TEAM_SUCCESS removes state.teams.teams[team.id] and clears selectedTeam
• SAVE_TEAM_SUCCESS updates state.teams.teams[team.id]

Profile Reducers

• CREATE_TEAM_SUCCESS adds a new team entry to state.profile.teams
• DELETE_TEAM_SUCCESS removes the team entry from state.profile.teams

Action Creators

• createTeam dispatches CREATE_TEAM_SUCCESS
• saveTeam dispatches the full team object
• deleteTeam dispatches DELETE_TEAM_SUCCESS with a teamId for removal

Firebase Data Layer

• createTeam returns the teamId for CREATE_TEAM_SUCCESS dispatches
• deleteTeam removes listeners have a team has been deleted