remove some empty lines to make the code more compact

save some lines

save some lines

scope improvements, designated initializers

+ use of designated initializers

Attributes GH PR #862: https://github.com/ArcticaProject/nx-libs/pull/862

Attributes GH PR #887: https://github.com/ArcticaProject/nx-libs/pull/887

At reconnect we check if a keyboard reset is required. If so, we are
calling the corresponding code from Keyboard.c. No explicit keyboard
code in Reconnect.c required.

fixes ArcticaProject/nx-libs#886

slight optimization

This resulted in a garbled option string on reconnect where everything
after the first '=' was lost!

Attributes GH PR #888: https://github.com/ArcticaProject/nx-libs/pull/888

The normal case was to use the builtin icons. There were two cases
where the icon file was read from disk:

1) /usr/NX/share/images/nxagent.xpm was existing which normally is not
   there

2) case 2 was not true and nxagent.xpm was existing somewhere in the
   PATH (!)

(replace nxagent.xpm by x2goagent.xpm if in x2gp mode)

Scanning the path from the PATH variable for xpm files is kind of
unexpected and dangerous, too (think of automounter triggers or
invalid xpm files).

Also remove the xpm files from the distribution.

Attributes GH PR #889: https://github.com/ArcticaProject/nx-libs/pull/889

This leads to a tremendous startup speedup (several seconds, depending
on latency) because libXpm had to do a lot of X requests (have not
further examined which). With this colour-reduced version things are
quick again for those connections without losing a lot of quality.

Fixes ArcticaProject/nx-libs#824

gimp refused to load it, nxagent crashed if this was loaded as icon file!

Attributes GH PR #878: https://github.com/ArcticaProject/nx-libs/pull/878

Most <int> options are <bool>. Change that and add missing
defaults. Also add list of descriptions for the defer option.