Added a Get method for the smart pointer classes

More compact, the most common method name in other smart pointer
classes. Please let us have a shorter method name!

Change-Id: Ida8953823dc65e32bbc7d4713d61482bd9124980
new class: vtkReduceTable

This class collapses the rows of the input table such that one
particular column (the IndexColumn) no longer contains any duplicate
values.

Change-Id: I03dddb9b1ebbe61ddd4955241ea58244322840b9
Merge topic 'reduce_table' into master

78b929c1 new class: vtkReduceTable
Merge topic 'sp-get' into master

f62731d8 Added a Get method for the smart pointer classes