This modificaiton to the estimates loader allows the caller to pass
in an equity pricing loader which can then be used to get split data
for sids. That split data is then used to do point-in-time adjustments
of estimates data.
TST: add test for multiple estimates columns
TST: add test for multiple datasets requesting different columns
TST: add blaze versions for all next/previous tests
MAINT: optimization - only look at assets appearing in data
TST: simplify test
DOC: add documentation for checkpoints
MAINT: explicitly cast event date field to datetime
MAINT: add back import
TST: fix indexing to remove setting wtih copy warning
TST: fix quarter normalization test
TST: change test name
BUG: remove arg
BUG: look at dict keys
TST: add test for windowing
MAINT: raise ValueError instead of asserting
TST: add assertion to check windowing
TST: parametrize test over number of quarters forward/back.
BUG: fix adjustment calculation logic for quarter crossovers.
TST: add test for previous quarter windows
BUG: fix bugs in calculating previous windows
BUG: fix missing value for datetime
TST: add test case for missing quarter