Collected small changes and fixes

[akohlmey]

Summary

This pull request combines a few bug fixes and multiple local/simple refactoring changes to increase code reuse.
In total this PR removes over 2200 lines of code by simplification or code reuse.

Related Issue(s)

Fixes #2676

Author(s)

Axel Kohlmeyer, Temple U

Licensing

By submitting this pull request, I agree, that my contribution will be included in LAMMPS and redistributed under either the GNU General Public License version 2 (GPL v2) or the GNU Lesser General Public License version 2.1 (LGPL v2.1).

Backward Compatibility

No known issues.

Implementation Notes

This PR contains the following individual changes:

• correct documentation of angle style cosine/periodic
• correctly attribute angle style cosine/squared as used in DREIDING
• make dihedral style table/cut a derived class of dihedral style table and remove redundant code
• consolidate documentation for dihedral styles table and table/cut into one file
• fix various typos in the manual
• simplify code using utils::strdup() and related
• reorder include files in some .cpp files
• major simplification of temperature/pressure/ke/pe compute creation in thermostat/barostat and related fixes.

Post Submission Checklist

• The feature or features in this pull request is complete
• Licensing information is complete
• Corresponding author information is complete
• The source code follows the LAMMPS formatting guidelines
• Suitable new documentation files and/or updates to the existing docs are included
• The added/updated documentation is integrated and tested with the documentation build system
• The feature has been verified to work with the conventional build system
• The feature has been verified to work with the CMake based build system
• Suitable tests have been added to the unittest tree.
• A package specific README file has been included or updated
• One or more example input decks are included