API: Mark seldom-used formats as deprecated

While it doesn't take a lot to maintain most of these, there is some
effort needed (e.g. wddx was breaking with HHVM). None have much if any
usage that seems likely to be actual code of some sort, and humans
should be able to read the jsonfm format as easily as dbgfm, dumpfm, or
txtfm.

Change-Id: I4e3d2ef59d4306756b289a4be46caef7d359ccef
Merge "API: Mark seldom-used formats as deprecated"