Merge pull request #2077 from rblomberg/yahoo-csv-url-fix

changed URL to the current CSV API for yahoo finance
Merge pull request #2100 from glyg/master

Remove DeprecationWarning in simple_linear_interpolation
Fix exception_to_str to work on Python 2.x
Merge pull request #2104 from mdboom/exception_to_str

Bug in cbook.exception_to_str() in v 1.2
Merge remote-tracking branch 'upstream/v1.2.x' into v1.3.x