pgr_sequentialVertexColoring GSoC-2020 Week 3

[krashish8]

• Created a separate branch pgr_sequentialVertexColoring in my forked repository for doing the implementation of this function. This branch is checked out from the previous pgr_depthFirstSearch branch.
• Opened an issue in pgRouting's main repository for the discussion of the new functionality, containing the function's name, signature, description, and usage. - Issue #1362
• Created a basic skeleton for C, C++, SQL code, and for the documentation and tests. Add all the required files:
  • doc/graphColoring/ - CMakeLists.txt, pgr_sequentialVertexColoring.rst
  • docqueries/graphColoring/ - CMakeLists.txt, doc-pgr_sequentialVertexColoring.result, doc-pgr_sequentialVertexColoring.test.sql, test.conf
  • include/drivers/graphColoring/ - sequentialVertexColoring_driver.h
  • pgtap/graphColoring/ - sequentialVertexColoring-edge-cases.sql, sequentialVertexColoring-innerQuery.sql, sequentialVertexColoring-types-check.sql, no_crash_test-sequentialVertexColoring.sql
  • sql/graphColoring/ - CMakeLists.txt, _sequentialVertexColoring.sql, sequentialVertexColoring.sql
  • src/graphColoring/ - CMakeLists.txt, sequentialVertexColoring.c, sequentialVertexColoring_driver.cpp
• Modified the files for the current implementation of the function.
• Added the function name in the configuration file - configuration.conf.
• Updated the signatures file to contain the signature of the new function - sql/sigs/pgrouting--3.0.0.sig.