HPPCRT-49: Heaps wrongly use Comparable/Comparator for contains(), removeAll(), equals().

[vsonnier]

One of my users remarked that it was either wrong to use the Comparable or Comparator for methods involving equality tests in heaps, such as:

• contains(),
• removeAll(),
• equals()

because indeed object equality is a different concept as object ordering, so that compareTo(obj) == 0 cannot be used in place of an object equals() when testing equality.
Consequently make so that the above methods for heaps use equals() instead of the comparison criteria as before.
Besides, that allows

• contains(),
• removeAll()

to be consistent with the other KTypeContainer implementations using equals().

[vsonnier]

Done in 9552bcf