removed old remnant, reference to `users` table
branch now uses R :-)
switching to R
- switched Email recipient field to R
- made Email play nice with embedded knitr figures (using a custom image upload function and PHPmailer), though there is one problem: mailinator which we use for testing, strips away all images and other funny business. should we, by default, send the email to the sender?
- made skipifs use R. Caching evaluated skipifs in item_factory (per page)
- refactored openCPU and RunUnit models
- translated all_widgets example table to english
- added two new fields to DB scheme, to allow for the day when we use knitr in survey item and choice labels
annoying duplicated git repo stuff
Merge branch 'develop' of https://github.com/rubenarslan/formr into develop

Conflicts:
	documentation/Example files/all_widgets.xls
substitutions as a separate option for surveys are gone, closes #24, because it is now possible to dynamically evaluate knitr mixed with markdown for survey item and choice labels
also switched pause and time branch to R, am not happy with how they deal with missing values yet, should probably switch the entire time logic to R when we have time, closes #2

also changed the schema to pave the way to fixing these issues #3, #1

I am closing #15 for now, because it was fairly easy to support figure attachments in emails using a custom image upload function in knitr (closes #25)

some other cleanup as well
Merge branch 'develop' of https://github.com/rubenarslan/formr into develop

Conflicts:
	documentation/Example files/all_widgets.xls
added a contraception selector to example files
dearyliewald first steps
Merge branch 'develop'

Conflicts:
	Model/Email.php
	README.md