(trunk, utils) in transmission-create, return an error if a user tries to manually set a piece size that isn't a power of two.

git-svn-id: svn://svn.transmissionbt.com/Transmission/trunk@14294 f4695dd4-2c0a-0410-b89c-da849a56a58e
tweak naming in the #include guard

git-svn-id: svn://svn.transmissionbt.com/Transmission/trunk@14295 f4695dd4-2c0a-0410-b89c-da849a56a58e
set utils/Makefile.am's noinst_HEADERS so the build doesn't break on units.h

git-svn-id: svn://svn.transmissionbt.com/Transmission/trunk@14296 f4695dd4-2c0a-0410-b89c-da849a56a58e
keep banging my hands against the keyboard until Jenkins is happy

git-svn-id: svn://svn.transmissionbt.com/Transmission/trunk@14297 f4695dd4-2c0a-0410-b89c-da849a56a58e