v2.8.1

1. Fix window leakage error when viewing patient details (#623)
2. Fix various performance issues (#628, #632, #633, #627, #643, #656 )
3. Integrate leak canary for debug builds (#634)
4. Add a splash screen (#638)
5. Add intro slides for first time users (#642)
6. Set a code style (#651)
7. Fix broken unit tests (#637)