General improvements and fixes

• Modify merge_tables behavior in case of identical column names in multiple
  tables
• Add cast option to update_col_from_series to handle type mismatches
• Updated logic for outputting HDF5 files
• Add file compression to run and write_tables
• Fix base year output for iter_var dependencies
• Add iter_step injectable to track current simulation step
• Change default behavior to output only local tables to out_run_tables
• Use sets instead of lists in to_frame