Resolve "Command line heterodyne code"

As an extension of #16 (closed) and !25 (merged), and to resolve #35 (closed), add a command line interface and pipeline for the heterodyne code as a replacement for lalapps_heterodyne_pulsar. This should work over the OSG, and by default it should perform the heterodyne in "one go" rather than as course and fine stages (although it should be able to do that too!)

Important Note: commit 5492ff33 means that this MR breaks backwards compatibility with HeterodynedData objects output to HDF5 files using version prior to this one.