addto_lists(): store the IP/Port that was used to *send*.

Avoids a DOS of sending a copy of a valid response with an invalid IP.
Unify most of handle_sendnodes[_ipv6]() into a common handle_sendnodes_core(), leave only a minimal trail.
Merge pull request #642 from FullName/dht_handle_sendnodes_unify

Unify most of handle_sendnodes[_ipv6]() into a common core.
Merge branch 'add2lists_forward' of https://github.com/FullName/ProjectTox-Core into FullName-add2lists_forward
Code cleanups.
Optimized data sending slightly more.
Started as a simple bugfix for wrap(), expanded to more detailed help.

nTox.c:
- flag[]: additional flag for special wrapping
- help expanded and split (to keep below 256 chars)
- new_lines_mark(): stores flag for special wrapping
- print_friendlist():
.  - extracted pattern for output
.  - added length of id string allocation
.  - replaced '\t' with '+ ', wrappers don't account for '\t'
- line_eval():
.  - removed a few do_refresh() directly after a new_lines() (calls do_refresh() at its end)
.  - 'h' (help): parsing of an additional character for f(riend) or g(roup)
- wrap():
.  - the major bugfix:
.    - no more endless looping if the input had a substring with no spaces
.      for more than line_width (e.g. ID of 78 and window smaller than 78)
- wrap_bars(): wrap() for "rich" messages, honors embedded '\n', breaks preferable at '|'
- print_help(): listed all options and added explanations
- print_invite(): fixed minuscule typo
- main(): made print_help() reachable again

nTox.h:
- majorly cut down to what is really needed
Merge pull request #643 from FullName/nTox-patches

Started as a simple bugfix for wrap(), expanded to more detailed help.
Merge pull request #3 from irungentoo/master

actual 11.13