Gaps in composite FIMs at cross section seams

[ar-siddiqui]

Issue transferred to flows2fim from ripple1d, some discussion exists there. https://github.com/Dewberry/ripple1d/issues/41

[ar-siddiqui]

Based on the discussion with the HydroVis team of OWP, it is realized that HydroVis might be using the individual reach FIMs without flows2fim composite FIM functionality. In that case, we need to resolve this issue at the Reach Based FIM level.