fix typo

disambiguation dilemma between "sauce" and "source"
Add default value tags to adfuller() docs
BUG: numerical precision in resid_pearson with perfect fit closes #1229
Merge pull request #1230 from josef-pkt/regression_resid_person_zero

BUG: numerical precision in resid_pearson with perfect fit closes #1229
Merge pull request #1198 from piskvorky/patch-1

fix typo
Linebreak at less than 80 chars
Merge pull request #1228 from gliptak/patch-1

DOCS: Add default value tags to adfuller() docs
fixes for weighted kernel fits
bug fixes
adding tests
BUG: kde normalize weights, adjust tests (use evaluate)
BUG kernels.CustomKernel missing asarray, add unittest (only Gauss passes)
TST: add test kde with weights, only Gaussian kernel
BUG: fix bounded support kde, divide by total nobs, enable test
TST: add tests for KDEUnivariate with weights, Cosine fails, some not available
ENH: add Cosine2 kernel, same cosine kernel as Stata closes #1245
ENH: kernels add _kernel_var(not used yet)
ENH add density var and conf_int to kernels, regression tests only
REF/TST: test for kernel constants
DOC kde with confint add example script