std::isnan() workaround for intel-11.1
fix for pgi
Clearer defaults from configure --help

This should solve Issue #249

Most of these changes turn the help message from "--enable-foo" to
"--disable-foo" for values of foo that are on by default.  A few
changes add the default argument in brackets to the help message.
Use libmesh_error_msg() where appropriate.
Update traffic.
Merge pull request #251 from libMesh/invert_help_text

Clearer defaults from configure --help
Disable fparser debugging functions by default

And fix the fparser Makefile so that whether they're enabled will
depend correctly on the configure options
Fixes for -Wshadow warnings

We're also going to have to do some ignore_warnings/restore_warnings
trickery before -Wshadow is useful again; my PETSc build has a few
cases of shadowing and Eigen is full of them.

Issue #24
Merge pull request #250 from libMesh/more_shadow_fixes

Fixes for -Wshadow warnings
Use libmesh_error_msg() where appropriate.
adding qhull
adding upstream Makefile
build Qhull as a contributed package
build Qhull programs and add them as a check target
descriptive comment about where the mysterious checks came from
Qhull does not install any headers, yet anyway.
avoid duplicate symbols in C++ library
adding CHANGES file to track changes
avoid unused variable warning
add new generated file