[#42646887] Add tube rack move action
[#42646887] Add comments, remove useless custom exception.
[#42646887] Allow nil value in []= method
[#42646887] Tube rack move specs pass
[#42646887] Small changes in the spec
Bump to version 0.26.0
Update doc
Merge pull request #94 from maxigit/42646887_move_tube_action

42646887 move tube action