don't auto position other floater when it is hosted

- Also reduced squiggle width from 6 to 4 and prevented running past the end of a word

Added checks for LLViewerRegion pointer in LLViewerObject being invalid.

Mindful that some autobuild packages populate only packages/lib/release
(rather than packages/lib/debug), Linking.cmake always appends
packages/lib/release to CMake's link_directories() directive. But since CMake
always appends CMAKE_BUILD_TYPE to those directories, we end up with a phantom
packages/lib/release/Release directory on the search path. This would be
harmless except that the Mac's 'ld' command produces a warning. These warnings
quickly make TC's "Important Messages" output useless. Try appending
packages/lib/release only when the build type isn't already Release.

WOLF-363: (partial) correct ordering of cleaning build dir vs running
          'autobuild install'