Adding @sjoeboo born_on fact

Adding the born_on fact written by @sjoeboo to the harvard module
This is work towards issue #1
Adding first pass at lifeclock fact
Added comments to the fact
using Date and Time to make the math more obvious
Merge pull request #3 from huit/use_date_math

using Date and Time to make the math more obvious
Fixed Travis Badge
Merge pull request #4 from huit/custom_facts

Adding "life-clock" fact and "born_on"