Resolve "add clang-format configuration file"

Closes #617

See merge request !453

- AllowShortFunctionsOnASingleLine set to None

- commented out IndentCaseLabels removed. Google default is used

- use Google default for SpaceBeforeCpp11BracedList and SpaceBeforeParens

Resolve "fix floating point comparisons in BoundaryGeometry"

Closes #611

See merge request !447

Resolve "Transversely shifted distribution in temporal monitors"  with additional fixes

Closes #609

See merge request !449

fix position of particles, spos and position of reference particle in temporal monitor; fix positioning of monitor in 3D space

Resolve "Opal version in master branch"

Closes #615

See merge request !450

- use std::isnan() in the obsolete ULP implentation too
- use constexpr for EPS

- use std::abs() instead of std::fabs()
- use std::signbit(n) instead (n < 0)

Merge remote-tracking branch 'origin/master' into 611-fix-floating-point-comparisons-in-boundarygeometry

Resolve "master does not compile any more"

Closes #612

See merge request !448

length_m has been removed but was still used in a constructor

Resolve "Transversely shifted distribution in temporal monitors"

Closes #609

See merge request !444

<cstring> is missing in two source files

See merge request !443

Resolve "define and set project wide editor variables"

Closes #610

See merge request OPAL/src!445

- configuration files for Emacs and Vim added
- plugin for Vim added

Small fixes

See merge request OPAL/src!441

Resolve "Opal-T fails to write LossDataSink if executed in parallel"

Closes #585

See merge request OPAL/src!439

Resolve "Compile error in unit tests"

Closes #600

See merge request OPAL/src!434

Resolve "Update Doxygen main page"

Closes #601

See merge request OPAL/src!435