Include a history section

[banesullivan]

Feedback from @jcfr

Including an "History" section is also sensible to acknowledge prior contributor and explain how things endup where they are:

• https://github.com/Slicer/slicer_download#history
• https://github.com/Slicer/SlicerSurfaceToolbox/tree/a1b6a037293aeb7847fabd6df68726f2fbbc1e2c#history

That's absolutely important for projects that have a history - the people/organization who deserve credit should receive that acknowledgment in the README, in my opinion