Remove leftover debug output.
Fix minimum build point generation being added twice to the account of mined build points.
Refactor g_buildpoints.cpp a bit.
Add current mine rate and stored build points to buildable status displays.
Store remaining BP in the main structure. Only lose a fraction if a BP storage gets destroyed.

The fraction of BP lost can be set in g_buildPointLossFraction.
Don't add or remove momentum when the main structure gets built or deconstructed.

For destroying main structures, a fixed value is assumed (20 BP).
For other structures, always use the build point price as the buildable's value.

This fixes #325.
Reward momentum to enemy attackers if a hurt structure gets deconstructed.
Rename g_confidence.cpp to g_momentum.cpp.
Fix build.
Merge branch 'gameplay/viech' into gameplay/testing