[GRASS5] GRASS 5.7.0 beta4

[Radim Blazek]

http://mpa.itc.it/radim/grass-5.7.0beta4.tar.gz

Significant changes in DBF driver, I have rewritten the code 
parsing and evaluating WHERE conditions. Testing of DBF driver 
is desirable, especially with complicated WHERE conditions.
I have added db.test but currently only one simple test is available,
run it anyway (db.test test=test1), database must exist and set by db.connect.

Small fix in Postgres driver ( escape backslash ).

NVIZ: added points option, select sites -> select vector.

Many new scripts and changes in tcltkgrass ( Michael Barton ).

This should be last beta, 5.7.0 next week.

Radim