Unit tests on Mac OSX

[ahornung]

Some units tests seem to fail under OSX, as reported by @smcgill3:

Running tests...
Test project /Users/stephen/src/octomap/octomap
      Start  1: MathVector
 1/14 Test  #1: MathVector .......................   Passed    0.00 sec
      Start  2: MathPose
 2/14 Test  #2: MathPose .........................   Passed    0.00 sec
      Start  3: InsertRay
 3/14 Test  #3: InsertRay ........................   Passed    1.09 sec
      Start  4: CastRay
 4/14 Test  #4: CastRay ..........................   Passed    0.45 sec
      Start  5: InsertScan
 5/14 Test  #5: InsertScan .......................   Passed    0.49 sec
      Start  6: ReadGraph
 6/14 Test  #6: ReadGraph ........................   Passed    0.02 sec
      Start  7: StampedTree
 7/14 Test  #7: StampedTree ......................***Failed    1.23 sec
      Start  8: OcTreeKey
 8/14 Test  #8: OcTreeKey ........................   Passed    0.01 sec
      Start  9: OcTreeIterator
 9/14 Test  #9: OcTreeIterator ...................   Passed    0.02 sec
      Start 10: test_pruning
10/14 Test #10: test_pruning .....................   Passed    0.03 sec
      Start 11: test_iterators
11/14 Test #11: test_iterators ...................   Passed    0.67 sec
      Start 12: test_io
12/14 Test #12: test_io ..........................   Passed    0.49 sec
      Start 13: test_mapcollection
13/14 Test #13: test_mapcollection ...............   Passed    0.22 sec
      Start 14: test_color_tree
14/14 Test #14: test_color_tree ..................***Exception: Other  0.13 sec

86% tests passed, 2 tests failed out of 14

Total Test time (real) =   4.88 sec

The following tests FAILED:
      7 - StampedTree (Failed)
     14 - test_color_tree (OTHER_FAULT)

./test_color_tree
test_color_tree(641) malloc: *** error for object 0x7fecb9415508: incorrect checksum for freed object - object was probably modified after being freed.
*** set a breakpoint in malloc_error_break to debug
Abort trap: 6

I ran valgrind: stderr: http://pastebin.com/3rwqP9iB
stdout seems to indicate it worked, when under valgrind: http://pastebin.com/AQ3KYe4x

test_pruning yeilds an error:

test failed (EXPECT_TRUE) in /Users/stephen/src/octomap/octomap/src/testing/test_pruning.cpp, line 84

The stamped tree unit test works once in a while, but its error is:

After 1st update (cube): Tree time 1365441319; node(0.1, 0.1, 0.1) time 1365441319
After 2nd update (single miss): Tree time 1365441319; node(0.1, 0.1, 0.1) time 1365441319
After 3rd update (single hit at (0.1, 0.1, 0.3): Tree time 1365441320; node(0.1, 0.1, 0.1) time 3221227518; node(0.1, 0.1, 0.3) time 1365441320
test failed (EXPECT_TRUE) in /Users/stephen/src/octomap/octomap/src/testing/unit_tests.cpp, line 300