Merge pull request #44 from Dick-Lane/master

Add units to statement of initial condition.
correct typo in solution text.
fix bug 2294 (finally).
Fix bug 2828
resolve (?) bug 2601: explictly note that all answer blanks must
contain values.
fix bug 2402: make answer display numeric, matching information available
to students.
fix bug 2605: add parens to clarify problem display.
Fix bug 2834, made variation of a problem and put them in a MLT group.
Fix bug 2836.
Merge branch 'master' of github.com:openwebwork/webwork-open-problem-library
Fixed bug 2786 duplicate problems
New linear algebra problems.
New linear algebra problems.
New abstract vector space basis problem.
New linear algebra problem.
New change of basis problem.
Increase sampling rate to disambiguate function approximation

- Increased the number of signal samples from 10 to 12, which means that the maximum and minimum values of the function are now in the list

- Rounded data to two decimal places
New linear algebra problem.
Merge branch 'master' of git://github.com/openwebwork/webwork-open-problem-library
Minor fix.