Queue::empty()
Path::step() dummy implementation
REBASEME: ShortestPaths
A rough sequential shortest paths implementation
REBASEME: path
Make edge accessors public
Path::step()
Do not explicitly add optimizations to build flags

Optimizations and debug symbols are controlled by choosing between Debug
and Release cmake build types.
smcsp: Remove unused defines
Add QtCreator project files to .gitignore
sequential: Handle a special case path pruning
generator: Default to positive weight limits