Additional Graphs

Graphs:
-relationship durations
-gap lengths
-partner turnover rate
-concurrency
-total lifetime partners
-network metrics
Clean Up:
-Grid queue creation and processes moved to a single for loop
-remove old debug statements
-functions for age, sex, and dnp migrated to initialization
Bug Fixes:
-Relationships ended early by time operator removal had incorrect end
time in the master relationship list. Added a post-processing step to
clean up to fix this.
-Update_grid_queue_for method incorrectly always added agents to the
grid queue. Now an "if" statement verifies that the agent should be in
the grid queue.