new rake task: set age_unit to be week for Virtual Liver old specimens which use week as age unit
new rake task: set age_unit to be week for Virtual Liver old specimens which use week as age unit

kjgarza/frame_experiment,HITS-SDBV/seek,aina1205/nmtrypi-seek,Virtual-Liver-Network/seek,stuzart/seek,aina1205/SysMO-DB-seek,Virtual-Liver-Network/seek,aina1205/SysMO-DB-seek,BioVeL/seek,aina1205/nmtrypi-seek,HITS-SDBV/nmtrypi-seek,SynthSys/seek,Virtual-Liver-Network/seek,kjgarza/frame_experiment,aina1205/nmtrypi-seek,BioVeL/seek,SynthSys/seek,aina1205/nmtrypi-seek,stuzart/seek,BioVeL/seek,kjgarza/frame_experiment,HITS-SDBV/seek,Virtual-Liver-Network/seek,SynthSys/seek,aina1205/SysMO-DB-seek,HITS-SDBV/nmtrypi-seek,kjgarza/frame_experiment,HITS-SDBV/nmtrypi-seek,stuzart/seek,SynthSys/seek,BioVeL/seek,HITS-SDBV/seek,HITS-SDBV/nmtrypi-seek,HITS-SDBV/seek