Pass Schedule by value and move

[sweemer]

Schedule is a relatively heavy data structure, consisting of a couple vectors and other members, and is a prime candidate for moving instead of copying.

In fact several constructors already accept Schedule by value and move, so I am simply fixing the ones that aren't.

For the most part the changes are straightforward, but one thing to point out is that in overnightindexedswap.cpp I had to replace overnightSchedule with floatingSchedule() to access the moved-to member variable instead of the moved-from constructor arg, which may not be obvious from the variable names.

Another thing to point out, again in overnightindexedswap.cpp, is that the constructors taking a single Schedule argument end up copying twice - once into fixedSchedule and once into overnightSchedule. Perhaps these constructors should be deprecated in favor of the ones taking both schedules? I think that would help make the code more explicit and readable as well.

[coveralls]

coverage: 72.497%. remained the same
when pulling bdbb8e1 on sweemer:pass-schedule-by-value-and-move
into 7c12452 on lballabio:master.

[lballabio]

In the future we might try to reduce the number of constructors, but my reason would be to enable keyword args in Python :)