Remove regtest actions, introduce build-all actions:
- regtest was not easy to use
- one may wish to simply build all samples
- introduce a per-sample automatic build

/trunk/docs/overview.txt | 19 14 5 0 ++++++++---
/trunk/samples/samples.mk | 92 49 43 0 ++++++++++++++++++++++++++++-------------------------
/trunk/ct-ng.comp | 8 5 3 0 +++--
3 files changed, 68 insertions(+), 51 deletions(-)

 # Compute x86_64-specific values

 CT_DoArchTupleValues() {

     # The architecture part of the tuple:

     CT_TARGET_ARCH="${CT_ARCH}"

 }