Define protobuf_c_default_allocator locally for protobuf 1.0.1.

The definition is no longer present in 1.0.1 because NULL is passed
as a parameter instead for the default allocator.  I assume the api
is the same since 1.0.0.
tagtransform: add color=* as alias for colour=*.

There was at one point a split in the data and also in the documentation
on the wiki on which tag to use, now colour=* has over 10 times the
number of uses in OpenStreetMap.