Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.

Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.

Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.

Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18425: Unittests for idlelib.IdleHistory. First patch by R. Jayakrishnan.
Issue #18226: Fix ImportError and subsequent TypeError in 2.7 backport.
Running py27\PCbuild> python_d -m test.regrtest -ugui test_idle
ignores the exceptions and gives no indication of a problem (fixed in 3.3).
Issue #18732: Remove unused* parameter output_sep from IdleHistory.History
and paired splits and joins that do nothing when output_sep is its default \n.
*It in unused in that the class in only instantiated once, with the default.
Make a few other changes in .fetch and its test.