Merge pull request #1007 from fxbenard/master

[i18n] > edd-media-button ready and add edd_get_label_singular to it
Store post_date_gmt too
Working on improved dates for API. #982
Refactored date ranges for sales. #982
Updated dates rangefor yesterday. #982
Updated dates for this month and last month. #982
Updated dates for this year and last year. #982
Added support for this_quarter and last_quarter sales. #982
Updated earnings with new date ranges. #982
Simplified previous month / year
reenabled caching
Corrected earnings totals
Added edd_sanitize_files_save()
Merge pull request #1014 from pippinsplugins/api-date-dev

Api date dev
Merge branch 'master' of github.com:pippinsplugins/Easy-Digital-Downloads
Correct W3TC cache check
minor improvements to edd_has_user_purchased()
Introduce edd_get_payment_user_id(). For #1010
Updated edit payment process / forms to use helper functions
Merged file download log meta box and sale stats metabox. Closes #1013