This commit was manufactured by cvs2svn to create branch 'RC_1_31_0'.
string::append(Iter, Iter)  seems to cause link failure for msvc-stlport.
try using += buf.substr(..) instead.  (the copy overhead is not critical)
a few precise changes :
 . free function boost::io::str moved into boost::, much more convenient due to Koenig lookup
 . added format::size() const  (avoids making the full string just to know the current size)
 . settled for clear() / clear_binds()
 . sample programs updated accordingly.
one occurence of clear_non_bound remained,  removed.
strange mismatch between declaration and definition of format::size() for MSVC7
maybe making size_type a typedef will help it
boost::io::str is now only an alias, use str directly (koenig lookup)

MSVC6 fail on
using boost::io::str;
so removed it.
dded  using boost::str, vc7 wasnt finding str.
new tests added from main trunk
. reflects updates in the code (member func size(), str() in boost:: )
. removes missing urls and update moved ones
. W3C validated
. minor added info (user type formatting note, etc)
"a note about performance" paragrpah added.
no actual change, just switched to include files with <foo/bar> instead of "foo/bar"
even if it's just for information,  bench_format.cpp updated, wasnt even compilable anymore..
fix for BCB 6 patch 4,  suggested by Pavel Vozenilek