STYLE: Fixing and refactoring linting#22863

Merged

datapythonista merged 19 commits intopandas-dev:masterfrom

datapythonista:lint_refactor

Oct 9, 2018

Commits on Sep 27, 2018

Refactoring lint.sh, wrong path pandas/src corrected, and made more compact and readable
datapythonista
committed

Commits on Oct 1, 2018

lint.sh renamed to code_checks.sh, and parameters now supported to call lint, patterns or doctests independently
datapythonista
committed
Fixing linting script name in travis
datapythonista
committed

Commits on Oct 4, 2018

Merging from master
datapythonista
committed