exclude eclipse project settings (can we also exclude other ide's project
settings?)
fixed bug that prevented the same TileSpec instance from rendering
correctly twice.  Renamed TileSpec.createTransformList() to
getTransformList() because the method does not necessarily create a new
instance.  Exactly this was the reason of the bug:

If the TileSpec had a list of Transforms, createTransfomrList() would
return this instance instead of a copy.  The instance is currently held
as a transient private member for later reuse.  Render.render(...) would
then add bounding box, pixel offset, mipmap scaling and result scaling
related transforms to this list, modifying it in place.
I have modified render(...) to copy the list, renamed the method, and
added care-demanding documentation.

Explanation: