Update README.md to 1.0.0

Release 1.0.0

Exclude test maps from package

Update priority-queue and bincode crates

Replace travis with GitHub Actions CI

Update link to DIMACS graphs

Update benchmarks (new hardware)

Point to benchmarks branch for DIMACS benchmarks

Store center node in replaced_edge_in field temporarily to save memory during preparation

Make ParamsWithOrder public

Add parameters to limit number of settled nodes during preparation, much faster preparation for certain graphs (#37)

Use unstable sort to speed up InputGraph::freeze

Minor cleanup

micros -> μs

Add convenience functions to save InputGraph to a text file, fix #35