pset 2 parson problem updates
small fixes to ps1 and StatementsandExpressions.rst
added Sequences chapter to pip2
Merge pull request #66 from aerenchyma/pset2-F14

Adding pset 2
release PS2
fix problem numbering in ps2
improved version of listassessments
sort order for answers in listasssesments
conflict resolution
Add ps1 solution set