Add minimal example code for gene leads kit

[eweitz]

This adds minimal example code for gene leads ideogram, helping onboard developers.

[coveralls]

Coverage: 86.647% (+0.1%) from 86.549% when pulling 035b063d0aea48e4a73f79adde62cec5e937fc19 on gene-leads-lite into 86639b208270992c94b36f02a3773e647ebdb203 on master.