Fix Issue 992: Singularity will not allow teleports above 4096, nor building above 4096.

Teleport height restrictions have been increased to 8192
 -The 4096 limit isn't in much of the teleport code anyhow, and it's certainly not enforced.
Building height restrictions are now hooked up to hippolimits, apparently they hadn't been
 -MAX_OBJECT_Z, and hardcoded 4096s now use gHippoLimits->getMaxHeight() instead
 -On floater_tools.xml max_val is left out, instead it is set with the rest of the gHippoLimits edit constraints in LLPanelObject::getState

indra/newview/llslurl.cpp

@@ -316,7 +316,7 @@ LLSLURL::LLSLURL(const std::string& slurl)
 			     (F32(mPosition[VY]) < 0.f) || 
                              (mPosition[VY] > REGION_WIDTH_METERS) ||
 			     (F32(mPosition[VZ]) < 0.f) || 
-                             (mPosition[VZ] > REGION_HEIGHT_METERS))
+                             (mPosition[VZ] > 8192.f/*REGION_HEIGHT_METERS*/))
 			    {
 			      mType = INVALID;
 			      return;