Add edge test cases

[jGaboardi]

Add edge test cases:

• utils._drop_geoms() 640d661
• utils._weld_MultiLineString()
  • 3+ parts with one set of equal sp/ep removed code; unnecessary in workflow
  • sp1 almost equals ep2 016b775
• utils.ring_correction()
  • disconnected ring 6c05b87
  • overlapping ring 6c05b87
• utils.record_filter()
  • column index ed038e7
  • single value in column ed038e7
  • multi value in column ed038e7
• utils.restriction_welder()
  • None-type KeyError 4b455ba
  • welding MultiLineString 81c685a
• utils.line_splitter()
  • no __iter__ attribute 4136694 refactored code
• utils._create_split_lines()
  • unaltered line 7d67f19
  • create endpoint for ring roads
• utils._find_break_locs()
  • case 1 56a9600
  • case 2 56a9600
  • case 3 68d129f
  • case 4 779ef85
  • case 5 (single) 779ef85
  • case 5 (multi) b8280d6
• utils._make_break_locs()
  • breaks and standard 56a9600
  • breaks and not standard line/mline 779ef85