Remove HashProvider and deprecate it

[thekid]

This pull request changes the way hashcodes are computed for HashTable, HashSet, Queue and Stack. Instead of keeping track of the hashcode when writing, it is computed when hashCode() is invoked, which occurs much less often!

This yields a speedup factor between 2 and 4 - see this measuring code:

# Before
$ xp -m ..\measure\ util.profiling.Measure Collections -n 100000
hashTable: 100000 iteration(s), 0.674 seconds, result= "value"
hashSet: 100000 iteration(s), 0.458 seconds, result= 1
queue: 100000 iteration(s), 0.576 seconds, result= "green"
stack: 100000 iteration(s), 0.404 seconds, result= "green"

# After
$ xp -m ..\measure\ util.profiling.Measure Collections -n 100000
hashTable: 100000 iteration(s), 0.332 seconds, result= "value"
hashSet: 100000 iteration(s), 0.249 seconds, result= 1
queue: 100000 iteration(s), 0.135 seconds, result= "green"
stack: 100000 iteration(s), 0.097 seconds, result= "green"

This pull request does not introduce a BC break. However, future major versions will remove the now-deprecated class HashProvider. Although it's a purely internal class is was not clearly marked as such and might have gotten used.