Streamline dump control options

- Rename `--dump-treei` option to `--dumpi-tree`, which itself is now a
  special case of `--dumpi-<tag>` where tag can be a magic word, or a
  filename
- Control dumping via static `dump*()` functions, analogous to `debug()`
- Make dumping independent of the value of `debug()` (so dumping always
  works even without the debug flag)
- Add separate `--dumpi-graph` for dumping V3Graphs, which is again a
  special case of `--dumpi-<tag>`
- Alias `--dump-<tag>` to `--dumpi-<tag> 3` as before

src/V3Force.cpp

@@ -46,6 +46,8 @@
 #include "V3Error.h"
 #include "V3Global.h"
 
+VL_DEFINE_DEBUG_FUNCTIONS;
+
 //######################################################################
 // Convert force/release statements and signals marked 'forceable'
 
@@ -305,5 +307,5 @@ void V3Force::forceAll(AstNetlist* nodep) {
     UINFO(2, __FUNCTION__ << ": " << endl);
     if (!v3Global.hasForceableSignals()) return;
     ForceConvertVisitor::apply(nodep);
-    V3Global::dumpCheckGlobalTree("force", 0, v3Global.opt.dumpTreeLevel(__FILE__) >= 3);
+    V3Global::dumpCheckGlobalTree("force", 0, dumpTree() >= 3);
 }