interp/remap: improve support for remapping builtin codes

The G_REMAPPABLE and M_REMAPPABLE macros were getting a bit baroque.
Replace these macros by a bitset lookups, add init code for same.
interp/remap: make G28/G28.1/G30/G30.1 remappable
interp/remap: add G28/G28.1/G30/G30.1 example to remap/getting-started
rtapi_compat: added rtapi_app checks to make sure the corresponding app
 	for a particular flavor is available
added xenomai_kernel
fix gcc version detection.
semicolon typo.
rtapi_compat: switched to checking for rtapi lib instead of rtapi app
Merge pull request #197 from kinsamanka/rtapi_compat_fix

Rtapi compat fix
Merge pull request #199 from bryant/small-fixes

Small fixes
betterer gcc version check.
Merge pull request #200 from bryant/small-fixes-fix

betterer gcc version check.
hal/halsampler: add -N <compnname> option

needed to wait for this component
also rewrite using getopt(3)
tests/abs.0: fix race condition

partially repairs https://github.com/machinekit/machinekit/issues/202
let's see how this works out, then fix the rest of them.
gitgnore lib/python/machinekit/__init__.py
Merge pull request #203 from mhaberler/fixsampler

halsampler - add -N <name> argument
Merge remote-tracking branch 'mah/remap-g30'
Merge pull request #206 from jasonpenn/master

Make G28 and G39 remappable
tests: rearrange invocation of halsampler to avoid race conditions

see also: https://github.com/machinekit/machinekit/issues/202

this fixes a wide range of runtests errors, from 'overrun detected
- re-running tests' to runtests with truncated output from halsampler


Signed-off-by: Michael Haberler <git@mah.priv.at>
Merge pull request #207 from mhaberler/fixsampler

tests: rearrange invocation of halsampler to avoid race conditions