[Harbour] hbmk2 new extensions

[Szakáts Viktor]

Hi All,

After a few days in SVN and actual usage (throwing out
every stuff related to old make systems), I have to say
I don't like the new extensions, so I'll revert them to
original state in the next few days, unless there is
some convincing input not to do so.

.hbl is too limiting. After all, it can be used to
give common parameters for any targets, not just a libs.
It will be restored to .hbp which means Harbour
Parameters, or you can also think of it as the perhaps
more intuitive Harbour Package.

.hbp will be restored to .hbt which means Target,
in sync with the - since finalized - '-target' options.

I'll leave .hbi for language files in the meantime.

Brgds,
Viktor