Print bilby version in `bilby_result`

It would be nice to print the version of 1) bilby being run and 2) bilby used to generate the run when starting bilby_result. The current output is

Python 3.7.1 (default, Dec 14 2018, 19:28:38) 
Type 'copyright', 'credits' or 'license' for more information
IPython 7.2.0 -- An enhanced Interactive Python. Type '?' for help.


Opened IPython terminal for result LABEL
Bilby result loaded as `result`

I would suggest adding a two lines with those two versions at the end of this, what do people think? I'm not sure if there are other command line tools that would benefit from having this.