Added save method to Acq2P class

Simplifies saving an acq object by overloading save. Should never be
accidentally called, because standard save command requires a string
input whereas method requires object input. By default uses the
defaultDir as write directory and the acqName as both saved file name
and as the variable the acq is internally represented by, but all
arguments can be modified
New acq property for metadata, size moved to corMov

Acq objects have a new metadata property that is filled during motion
correction. Movie sizes were also moved from the derivedData field
(which really should be for non-essential info), to an array in
correctedMovies. For simplicity / compatability with the correctedMovies
field format, and because it is conceivable at some future timepoint,
each slice and each channel receives its own movie size array. There is
no disadvantage if this proves redundant since the storage space is
miniscule.
Updated functions to work with new movie sizes

Multiple functions expect the old location of the movie sizes field. If
an error is thrown after updating any of these functions, run the
addMovieSizes update function, which will take either an acq with no
movie sizes, or with movie sizes in the old format, and fill in movie
sizes in the current format