Fix metric arc tolerence to same value as imperial

Also add an ini file field and allow user variance of arc tolerances
within preset limits
Squashed 'src/machinetalk/proto/' changes from 4495f3e..3e96abf

3e96abf Merge pull request #9 from strahlex/halrcomp-no-create
a9c12fb for-proto: add no_create flag to Component submessage

git-subtree-dir: src/machinetalk/proto
git-subtree-split: 3e96abfcdb35b6776d185311803e1519b8f7ebca
haltalk: do not create component on MT_HALRCOMP_BIND if no_create flag set

this makes creating UI's matching the HAL config a bit easier