werkblad elementaire deeltjes

opgaven elementaire deeltjes
added sun

added figure by david F.
changed quotation marks

fixed wrong quotations
update of uitwerkingen
update uitwerkingen

last update of uitwerkingen elementaire deeltjes
Copied style to style_werkblad

Start work on a separate style for werkblad files.  For question
environments a lot of work is already done by the exam class, but that
class does not play nice with our styles.  I'll try to fix that.
Fixed some typos in CONTRIBUTING
Style file now works with exam class.
Broke out common style code
Merge branch 'layout' into elementaire_deeltjes
Customized werkblad style

We can now print a specified number of lines, yay!
Werkblad ED now uses new werkblad style

Numbering of questions is automatic. Use of \paragraph, \\ line breaks,
manual ruling inside center environments and \bigskip is no longer
necessary.
Remove old werkblad example
Use flag in TeX file for printing answers
Solutions correctly implemented
Answers elementaire deeltjes in werkblad

Copied from old 'uitwerkingen'
Removed old uitwerkingen

Replaced with minimal template file
Fix for question labels

There was an extraneous dot because I didn’t correctly use the
definition commands.
Fixed serial number of werkblad
Added elementaire deeltjes to index