Add Panel method to rearrange axes

[wesm]

No description provided.

[jreback]

e.g. right now p.swapaxes(axis1='items',axis2='minor').swapaxes(axis1='items',axis2='major') is required to reorder all axes
maybe: p.reorder_axes(items = 'minor', major = 'items', minor = 'major') would do the above; if you specify None for an axes should leave it alone?
admittedlty this is not that common, but for efficiency might be useful

use case was this:
df = DataFrame(fields x tickers)
p = Panel({ date : df }) -> items = date, major = tickers, minor = fields

as I use panels to represent items x time x tickers as a general rule

[wesm]

@changhiskhan can you add this, let's call it transpose:

p.transpose('major', 'items', 'minor')
p.transpose(1, 0, 2) # equivalently