Add merge() algorithm

This implements the merge() algorithm which merges two
ranges of sorted values into a single sorted range.

The current implementation uses a simple serial merge
algorithm. A GPU optimized version is coming soon.
Add lambda wrapper for length() function

This adds a lambda wrapper for the length() function which
allows it to be used in lambda expressions.
Add test for sorting vectors by length

This adds a test for the sort() method which sorts a container
of 3D vectors by their length. This uses a lambda expression to
generate the compare function for the sort() algorithm.
Fix test module name for TestRadixSort

This fixes the module name for the radix sort test.
Fix test module name for TestInsertionSort

This fixes the module name for the insertion sort test.