Merge revisions 14222, 14268, and 14270 from the BUF_REMOVAL branch to trunk.

Merge revisions 14222, 14268, and 14270 from the BUF_REMOVAL branch to trunk.
Assorted fixes in exp-bbv to eliminate a few buffers.
Implement a suggestion found in the massif source, namely to add the
equivalent of fprintf to m_libcprint. Good suggestion. Thusly
- VgFile: similar to FILE; buffered output, 8k buffer
- VG_(fopen): similar to fopen, but with arguments as in VG_(open)
- VG_(fprintf) and VG_(vfprintf): like [v]fprintf with VgFile 1at argument
- VG_(fclose)
Change massif, exp-bbv and cachegrind to use this functionality.

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@14678