Fix for "make distcheck"

When run on a tree that hadn't yet been built normally, distcheck was
dying when it failed to find libmesh/libmesh_config.h
Fix for "make distcheck"

When running on a fresh source tree, distcheck was dying when it
couldn't build some of the files we'd told it to distribute.
Re-bootstrap after previous two commits
Fix "make distcheck" with mpirun

If we use more than one processor we get more than one vtu output
file, so we need a rule rather than a hard-coded list to clean them.
bootstrap with previous commit
We still want some programs iff FPARSER_DEVEL

I mistakenly moved these outside that test when I was moving nearby
build rules.
Re-bootstrap with last commit
More fparser DISTCLEANFILES

This finally gets 'make distcheck' working on my system.  Still need
to figure out the "'make all' needs yacc now" bug that previous changes
introduced.
Re-bootstrap with last change
Move one BUILT_SOURCES back into if FPARSER_DEVEL

This might be enough to fix the yacc dependency
Re-run bootstrap with previous commit
Merge pull request #318 from libMesh/distcheck_fixes

Distcheck fixes