Fix changefeed bug, add some debug-mode instrumentation to mailboxes.
Fixed capitalization.
removing docs/internal

over-the-shoulder from @danielmewes
initial commit for #2432 merge the rql_test/test_utils.py and common/driver.py

common tools update needed for the merge
switching all of the ReQL tests away from test_util to driver

assorted grumbling about the name "driver"
first round of fixed problems
second round of fixes
third round of fixes
fourth round of fixes
final fixes for review
changes from pre-review
fixing typos in indentifier names
fix for bug D3926
re-structuring cursor_test.py into the three respective .test files
Merge branch 'larkost/2432-combine-test_utils-driver.py' of https://github.com/rethinkdb/rethinkdb into larkost/2432-combine-test_utils-driver.py