Merge pull request #577 from adamarla/master

2 questions added
[cron-git-commit] @ 14.16
[Big]: Layout controlled via TeX itself ...

New macro(s): \setPageBreaks{a,b,c,d ... }
Will trigger a \nextpg after the specified subparts

Page/Question/Subpart numbering reset within \DocAuthor itself
Removed textpos package ...

xstring is now includeded from with tufte-exam.cls itself
Question versions also being set by callbacks

Using list processing provided by etoolbox throughout, ie. for version setting and for page-breaking.
Defaults and sanity checks provided for various macros and callbacks
Question versions by \setAuthor

No explicit call to \setcounter{rolldice} required
Merge remote-tracking branch 'abhinavs/master'
Defined callbacks for \BeforeBegin and \AfterEnd{questions}

If we wrap each student's questions in its own questions environment, then
we can attach before- and after- callbacks to make the TeX code even more
elegant
Copyright notice now appended by \BeforeBeginEnvironment{questions}
 minor cosmetic changes
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'abhinavs/master'
Needed to define else clause for \ifnumodd in \AtEndEnviroment{questions}
Merge remote-tracking branch 'abhinavs/master'
 Forgot to provide else clause for \notblank
Merge remote-tracking branch 'abhinavs/master'
Mandatory nextPg after last subpart (for a given student)