build: fix webtalk clean target

cant have multiple identically named targets - newer overrides older.
Merge pull request #398 from mhaberler/master

build: fix webtalk clean target
gmoccapy_1_3_5_1 - updated to current version

A lot of changes , please see release_notes.txt for all details

hal_gremlin.py has been changed to send a signal if bad gcode is found.
and gmoccapy does not react to that signal.

Signed-off-by: Norbert Schechner <nieson@web.de>
interp/remap: make M100-M199 remappable

a REMAP=M1xx ... now takes precedence over an external executable
with the same name.
Merge pull request #404 from gmoccapy/master

gmoccapy_1_3_5_1 - updated to current version
Merge pull request #405 from mhaberler/m100-m199-remappable

interp/remap: make M100-M199 remappable
Merge branch 'master' into docs-devel