Resolve "Unused classes in src"

Closes #491

See merge request !307

Resolve "BEAM without particles specified crashes"

Closes #490

See merge request !305

Resolve "Clang compiler warning for IntTSC (-Wsign-compare)"

Closes #487

See merge request !301

Resolve "clang compiler warnings in unit tests"

Closes #489

See merge request !304

Resolve "clang compiler errors for MPI_AllReduce (-Wtype-safety)"

Closes #485

See merge request !303

Merge branch '488-clang-compiler-error-unmatched-template-parameter-const-centeringenum' into 'master'

Resolve "clang compiler error: unmatched template parameter `const CenteringEnum*`"

Closes #488

See merge request !302

Resolve "clang compiler error for VerticalFFAMagnet"

Closes #484

See merge request !299

Resolve "Compiler warnings from boost headers stops compilation"

Closes #483

See merge request !300

Resolve "Broken link in Readme"

See merge request !298

Resolve "What is the status of OPAL Map?"

Closes #464

See merge request !294

Use std::round(x) instead of std::floor(x+0.5)

See merge request !297

use c++11 std__math methods instead of own classes

See merge request !296

Resolve "`VALUE` command does not print variable names"

Closes #480

See merge request !295

Resolve "IPPL tests and Boost timer"

Closes #479

See merge request !293

Resolve "fix warnings with GCC 9.2 and -Wextra and some cleanup"

Closes #478

See merge request !292

Resolve "asciih5block not working with recent H5Hut library?"

Closes #469

See merge request !281