Ignoring merges in analysis

Changes to the way the git log interactions are written in local_git_repo ::  all_revisions_oldest_first

The intention is that all commits on the current branch (i.e. master) are considered, along with any commits that represent a merge into master from a branch.

Previously, commits that where merges from branch -> master where ignored, creating misleading deltas for the analysis of the commit that followed the merge