Added support for $min, $max update operators
fix min,max tests for 1.08
Merge branch 'ISSUE-671' of https://github.com/rlodge/morphia into rlodge-ISSUE-671
[Issue 671] Split the tests so they are testing Just One Thing (and removes the need for comments).
[Issue 671] Updated TestUpdateOps to use assertThat and hamcrest matchers as per our newer style of testing.