Changed behavior of gt_feature_node_set_source
Merge branch 'master' of https://github.com/genometools/genometools
Merge pull request #29 from standage/master

Change behavior or gt_feature_node_set_source to enable resetting source value
refactor and rename

removed indirection for reading and writing were possible
Merge pull request #30 from Garonenur/dw

refactor and rename