bug correction, egoAlterCombi improved, and further small changes

[TomSnijders]

Description

• Function preprocessEgo now is defined properly for several classes of generic functions in \src\model\effects\generic. This is a bug fix.
• R function egoAlterCombi for GoF now omits values where the behavioral variable is NA.
• Correction to the non-exported function selectionTableWithMax.
• Some small additions to diagnostic output of siena07 for verbose=TRUE.

Checklist:

Checks

• The package builds on my OS without issues
• My changes generate no new warnings

Documentation

• I have commented my code inline, particularly in hard-to-understand areas
• If function added/modified, I have added/modified documentation (in .R file)
• I have added a description of all changes to this pull request above and to the NEWS.md file
• I have bumped the version in the DESCRIPTION and man/RSiena-package.md files by the appropriate increment, and renewed it to obtain agreement with the github version.