Fix bugs on Export Page

[briri]

• Cannot export plans as PDF or text (all other formats ok) - gives error message “RuntimeError in PlansController#export”
• Do not display question numbers or html tags in “Sections” menu on Export page (screenshot below: #1 from Roadmap to compare with #2 from DMPonline). Tags also appear in Plan Details page. This might just be an issue with the DMPTuuli data for this template; I’m not finding html tags in other templates...
• Exported DOCX contains questions and answers - it should only contain answers. Again, this is attributable to DMPTuuli template data and doesn’t appear to be a global problem.
• Adding issues from Export section above: PDF export is now working but when I change PDF Formatting settings the only change that takes effect is font size; Times New Roman font does not work and neither do margin adjustments
• Why are there separate fields for Project Name and Title? Is this for multi-phase plans? If necessary to have both, it would be better to include the Title as an admin details field under “Included Elements” so users can turn it on/off Added to Pivotal
• Admin Details options do not reflect the info that users enter on the Plan Details page (screenshot #3 below) - I’m confused by inconsistent use of terms “plan details” “project details” “plan name” “project name” “Title/DMP title” - create Pivotal ticket Added to Pivotal  See screenshots in the 'Export' section of: https://docs.google.com/document/d/1xsH_wXQfYpAlfOmYAJ_VI89FEpW0wX7-FS8_tcXxrvY/edit

[briri]

• Added gem that will install binaries used by the wicked_pdf gem, so if bundle install works on the instance the PDF export option should now work.
• Removed html content from the sections section of the export form. Cannot reliable remove question numbers because they were entered manually by the user into the name of the section as text. If its a serious issue we can investigate ways of trying to remove these number via regex. Users may want to see it though.
• All plans export with the question and the answer (even in DMPOnline v4) it may just look confusing perhaps if the question is long or not worded like a question (e.g. 'the expected schedule for data sharing' instead of 'What is the expected schedule for data sharing?').
• Changing font selection, font size and margins appears to be working. User has to click 'Save' before clicking 'Export' for the change to take affect though.
• I only see a 'Plan Name' not a title. Not sure which screen this issue applies to.
• Updated locale files so that 'Added Elements - Details' match the labels shown to the user when they edit the plan details