Clarify what the unused fields are for
Added method to find the next (positive) power of two
Do not allow push of null elements in the stack
Removed redundant tests
Implented add/remove methods for LFStack that won't raise exceptions on empty stack
Set gradle/java's group
There's no need to CAS-loop in peek()
Miscalculated the required padding
Include support for JMH-based benchmarking
Document how to run the benchmarks
Benchmarked LFStack