Add checkpoint timer stats. #1374
Fix error wrapper usage.  Change units to msecs. #1374
Allow unicode typed objects in Python with S/s formats.  refs #1187.
Includes tests that trigger the problem.
Revert skip list probability back to 1/4.
Move checkpoint timing code lower and only time full database
checkpoints. #1374
Merge branch 'develop' into checkpoint-timers
Merge pull request #1375 from wiredtiger/checkpoint-timers

Add checkpoint timer stats. #1374
Add a stat macro so can directly access connection statistics' values;
maintain the checkpoint statistics in the WT_CONNECTION_IMPL statistics
structure fields instead of in separate WT_CONNECTION_IMPL fields.
Merge pull request #1377 from wiredtiger/python-unicode

Allow unicode typed objects in Python with S/s formats.  refs #1187.