Clarify requirements on input table
Add 1-1 examples
Add example with non-symmetric distance function
Format tables in comments
Add 1-1 section title
Add 1-Several example
Add 1-All examples; adapt other examples
Align example data
Add Many-to-Many example
Add transpose example
Simplify signatures
Add WDO svg
Add illustration, explanation and see also
Put parameters explanation in order of appearance
Add undirected example
Add unweighted example
Merge pull request #384 from agouge/ghp-st-spl-examples

Add examples for ST_ShortestPathLength