Flow cutter can fail to parse output file when no decomposition is found

[brenjohn]

When flow cutter fails to find a tree decomposition for a graph it often generates an empty output file. However, there are edge cases where flow cutter will write a comment to the output file indicating that no tree decomposition was found followed by several empty lines. These empty lines can cause an error as when the output file is being parsed it is assumed that lines that do not begin either a 'c', 's' or 'b' identify an edge in a tree as described in appendix B here https://pacechallenge.wordpress.com/pace-2017/track-a-treewidth/

[brenjohn]

@JuliaRegistrator register()

[JuliaRegistrator]

Registration pull request created: JuliaRegistries/General/34424

After the above pull request is merged, it is recommended that a tag is created on this repository for the registered package version.

This will be done automatically if the Julia TagBot GitHub Action is installed, or can be done manually through the github interface, or via:

git tag -a v0.1.6 -m "<description of version>" 72fc2cfcc49f6101c0607b88fb91cbd6afefde76
git push origin v0.1.6