There's been some changes to the checkout strategy, especially the
SAFE_CREATE mode, which is now the RECREATE_MISSING flag, though that
shouldn't be necessary to use in the general case.
The largest changes come from the removal of the signture from
ref-modifying functions/methods and the removal of the reflog string in
all but those directly related to moving references.
The option to ignore the server's certificate has been removed, replaced
witha callback for the user to perform their own checking.
Remote.Fetch() now performs opportunistic updates and takes a list of
refspecs to use as the active set for a particular fetch.
Carlos Martín Nieto
David Calavera