fix matrix_toarray bug, crashed for empty rows
add ConstrainedOperator, fixes solve w/constraints
replace axpy by update
replace add_left/right_precon by set_precon
add Map.used member
fix add_global bug
add matrix addition
introduce Matrix/VectorBuilder,add matrix addition
change Matrix.add return value to Matrix
add Operator.linearproblem method
include trilinos Makefile
replace params_set<T> by params_update from xml
automatically scan for LibMatrix methods
change params_print log level
Added logical AND operator