helper function 'or' and 'but' rule
merge and-rule
name correction
Debugging for removing the locks in calling pattern matcher.
Merge branch 'master' of http://github.com/opencog/opencog into PM
Removed a lock , raised the speed of mining
Merge branch 'master' of http://github.com/opencog/opencog into PM
Test Linas's fix  #1026
Rewrite the 2-atomspace code to use nested atomspace.
Changed 1-gram index order. Changed flush progress output .
Merge branch 'master' of http://github.com/opencog/opencog into PM
Added installation of graphviz to instructions
Merge pull request #1032 from anitzkin/patch-1

Added installation of graphviz to instructions
atomtable: more dbg statements
unit test: Use the official atomspace API.
atomsapce test: extend the threading test.
Atomspace: add an extended deletion test.
test: add a note ...
Try to make the unit test more challenging.
try to make test case even harder.