Source & Tools: No EOL Whitespaces

End-of-line (EOL) whitespaces are verbose and increase diffs and
merge conflicts over time.

Cleaned them up for the `Source/`, `Examples/` and `Tools/` directory
with the following bash one-liner:

```bash
find . -type f -not -path './.git*'  \
  -exec sed -i 's/[[:blank:]]*$//' {} \;
```

Committed as generic user so git does not credit the many lines
to me:
```bash
GIT_AUTHOR_NAME="Tools" GIT_AUTHOR_EMAIL="warpx@lbl.gov"  \
  git commit
```

1 files changed, 1 insertions, 1 deletions

diff --git a/Source/FieldSolver/SpectralSolver/SpectralKSpace.cpp b/Source/FieldSolver/SpectralSolver/SpectralKSpace.cpp
index 6fe5e3939..aee131324 100644
--- a/Source/FieldSolver/SpectralSolver/SpectralKSpace.cpp
+++ b/Source/FieldSolver/SpectralSolver/SpectralKSpace.cpp
@@ -149,7 +149,7 @@ SpectralKSpace::getSpectralShiftFactor( const DistributionMapping& dm,
 #else
             shift[i] = std::exp( I*sign*k[i]*0.5*dx[i_dim] );
 #endif
-        
+
         }
     }
     return shift_factor;