Refactor private random seed code
Fix private random seed mechanism

- Introduce randomInt/p_randomInt to generate random integers in a half-open range
- Stop using runif to generate integers
- Explicitly reset the private seed during .onLoad. I was getting the same "random" numbers from Shiny every time I restarted R!
Rename tempSet to withTemporary
Fix createUniqueId logic
Fix tests
Merge pull request #434 from jcheng5/private-random

Refactor private random seed code