(trunk) replace the tr_metainfo_builder.isSingleFile and tr_info.isMultifile fields an 'isFolder' bool in both structs.

This makes the variable naming more uniform. It also clarifies the information we're really trying to convey -- previously, isSingleFile was false whenever the torrent held a directory tree, even if there was only a single file in the tree.

Sync the Mac OS X client's use to match the libtransmission variable names.


git-svn-id: svn://svn.transmissionbt.com/Transmission/trunk@14290 f4695dd4-2c0a-0410-b89c-da849a56a58e
in makemeta-tests, add tests to generate a .torrent file from a folder of randomly-generated files.

git-svn-id: svn://svn.transmissionbt.com/Transmission/trunk@14291 f4695dd4-2c0a-0410-b89c-da849a56a58e