Add common interface for field selectors#807

Merged

mziccard merged 3 commits intogoogleapis:masterfrom mziccard:field-selector

Mar 31, 2016

+444-209

Commits on Mar 29, 2016

Add common interface for field selectors
mziccard
committed

Commits on Mar 30, 2016

Refactor field selection and helpers
mziccard
committed

Commits on Mar 31, 2016

Minor refactoring for SelectorHelper
mziccard
committed