added commutative/associative/distributive theorems
Merge pull request #15 from yushan87/master

added commutative/associative/distributive theorems
fixes for Murali for his SPLASH demo and class
changed 'Length(Q) /= 0' to 'Is_Not_Zero(Length(Q))'
got rid of the requires clause in Exchange2 - that is an exercise for the attendees!
fixed space/tab issues
Merge pull request #16 from yushan87/splash-fixes

fixes for Murali for his SPLASH demo and class
changed from Length(Q) /= 0 to Is_Not_Zero(Length(Q))
Merge pull request #17 from yushan87/splash-fixes

changed from Length(Q) /= 0 to Is_Not_Zero(Length(Q))
changed the zero length theorem in String_Theory
Merge pull request #18 from yushan87/splash-fixes

changed the zero length theorem in String_Theory
fixes for Murali (10/10/2013)
Merge pull request #19 from yushan87/splash-fixes

fixes for Murali (10/10/2013)
changes for Murali (10/11/2013)
Merge pull request #20 from yushan87/splash-fixes

changes for Murali (10/11/2013)
more fixes for Murali
tab issues
Merge pull request #21 from yushan87/splash_fixes

Splash fixes
changed variable name to make it less confusing
fixes for the read method in java