MNT: Update CHANGELOG for 0.3.1

MNT: Update CHANGELOG for 0.3.0

BUG: Aggregate Equity on 'last' when plot resampling

Fixes kernc#162

Thanks @eervin123

BUG: Fix AssertionError on multiple calls to `trade.close()`

DOC: Account for markdown link bug in Jupyter

DOC: Document `Backtest(..., exclusive_orders=)` parameter

Oops.

Fixes kernc#123

Merge PR kernc#47 (Order/Trade/Position API)

MNT: Avoid testing via deprecated setup.py test_suite (kernc#107)

BUG: Restore support for passing tuple of colors to Strategy.I

Broken since kernc@bae9340

MNT: Install dependency pre-releases on CI