[MAT-403] Move the off-heap memory manager into OG-Maths.
[MAT-403] respond to PR comments.
[MAT-403] respond to PR comments, missed one instance.
Merge pull request #109 from OpenGamma/MAT-403

Mat 403. Add off heap memory manager.
[MAT-343] Always specify expected exceptions

The use of ASSERT_ANY_THROW/EXPECT_ANY_THROW allows for things to
go wrong that we're not expecting, and still get a test pass. This
commit changes all ASSERT_ANY_THROW and EXPECT_ANY_THROW for
ASSERT_THROW and EXPECT_THROW.

Additionally, after doing this it was discovered that conversion
of real diagonal and real sparse matrices to Complex16AoA was not
actually working, and was throwing an rdag_error. Therefore,
support for attempting to do this has been removed from
Complex16AoA.