Rename sendListRequest_'s maxResults to pageSize

The original name was misleading. It's now called pageSize, and
maxResults will be actually used to limit the number of results
returned. Also support nextPageToken so that the next page of
partial results can still be requested when necessary.

Also modify getAll and getChanges to support these two options. In
addition, a new constant DRIVE_API_PREFERRED_PAGE_SIZE is added and
set to 100 by default.
Add an option for metadata with createFolder

We need to set the folder's modification time when it's first created.