Implement JoinedMultiVector type
extra JoinedMultiVector test
fix elementMin bug
docs
make IndexVector immutable
remove unnecessary code
improve IndexVector getElements
specialised JoinedMultiVector join
better vector joining
add tryEfficientJoin function for vectors
efficient join for ZeroVectors
efficient join for AArrayVectors
add AJoinedVector abstract class
lift isView method to common implementation in AJoinedVector
make RepeatedElementVector extend from ASizedVector
remove AConstrainedVector
efficient join for JoinedVectors, remove tree balancing code
doc edits
more efficient JoinedVector joining
more efficient joining