Rename UnsafeParallelTransaction to DisjointParallelTransaction

Fixes #12
Include additional renames in this context

* All named Unsafe* (classes, members, etc.) within this context were renamed
  Disjoint*
Merge pull request #15 from smmf/fix/issue-12

Rename UnsafeParallelTransaction to DisjointParallelTransaction
Remove old scripts for parallel nesting examples
Merge pull request #16 from nmldiegues/fix/issue-12

Remove old scripts for parallel nesting examples