added check if is_dirty is already set#215

PaulSchweizer merged 2 commits intomasterPaulSchweizer/flowpipe:masterfrom

214-setting-is_dirty-on-a-node-with-a-lot-of-ancestors-is-quite-slowPaulSchweizer/flowpipe:214-setting-is_dirty-on-a-node-with-a-lot-of-ancestors-is-quite-slowCopy head branch name to clipboard