Task:     Found by Sebastian while adjusting Bitrock
RevBy:    Sebastian
AutoTest: None
Details:  -

reported by J Hseu

    Details:  also rename 'atEol' to 'atEndOfLine'

    Details:  tank count() into account, fix cursor positioning after undo

    Details:  fix behaviour of 'r'

    Details:  was not recorded onh the undo stck

    Task:     180315
    RevBy:
    Details:

    Details:  prevent creation of empty "groups" that required
additional 'u' key strokes to 'undo'

    Details:  was broken due to wrong cursor selection approach

Many singletons have their own instance() method, in which case there is
no need to use ICore::instance() to get access to them.

    RevBy:    partially by dt

The instance method has been moved to ICore, so there is generally no
need to include coreimpl.h anymore. Many objects accessed through this
core instance also had their own static instance methods.

Don't display the useless "Other" category, since the categorization of
commands isn't used anywhere (candidate for removal).

Filter out accelerator ampersands, since they aren't interesting here
and reduce the effectiveness of searching.

This makes both source and log files more readable and also prevents
gdb from applying extra quoting of its own.