Merge pull request #4092 from jtratner/refactor_string_special_methods

CLN: Refactor string special methods
ENH: (GH3863) Timestamp.min and Timestamp.max return a valid Timestamp
Merge branch 'timestamp_min_max' of https://github.com/SleepingPills/pandas into SleepingPills-timestamp_min_max

Conflicts:
	RELEASE.rst
	doc/source/v0.12.0.txt
TST: Change test_html to use stored data.

+ Change up test decorators so no tests marked as network and slow.