templates: split getgraphnode() body into two functions getgraphnodecurrent() is checking if the node is currently checked out and getgraphnodesymbol() is checking properties that have more to do with the stored data and the DAG.

hgweb: wrap {branch} and {changesetbranch} by hybridlist() This is also a 0/1-length list of a simple value, can be a hybrid list. Appears that we have many {branch} variants.