2012.4: update release notes
2012.4: update news
2012.4: bump version number
make view button to print view and roll as arguments of postproc.py

- update ViewerGUI._button_view_fired()
fix describe_geometry() of membranes for CMapping
new BulkActiveTLTerm (dw_tl_bulk_active)

- new dq_tl_he_stress_bulk_active(), dq_tl_he_tan_mod_bulk_active()
remove unused code path in BasicEvaluator
clean up sfepy/fem/problemDef.py
move time stepping solvers to new sfepy/solvers/ts_solvers.py

- clean up sfepy/solvers/ts.py
redesign time stepping, unify use of stationary and evolutionary solvers

- new StationarySolver
- update PDESolverApp.call()
- update TimeSteppingSolver - change __init__(), __call__() arguments, remove
  .set_step_fun()
- remove solve_stationary(), solve_evolutionary()
- move prepare_matrix(), prepare_save_data(), make_implicit_step(),
  make_explicit_step() into sfepy/solvers/ts_solvers.py
- new get_initial_state()
- update SimpleTimeSteppingSolver.__call__() to implement fully the time
  stepping loop, new .solve_step()
- update ExplicitTimeSteppingSolver, new .solve_step
update standalone examples for new time stepping
set ts directly in ProblemDefinition.update_time_stepper()
new AdaptiveTimeSteppingSolver - implicit adaptive time sptepping solver

- new get_min_dt(), adapt_time_step()
- new VariableTimeStepper.from_conf(), .set_from_ts(),
  .set_n_digit_from_min_dt()
- update VariableTimeStepper.set_step() to allow only step = 0
- update VariableTimeStepper.__iter__() to include t1
update linear_elastic_damping.py example to use adaptive time stepping
fix import of HomogenizationApp in micmac.py
clean up sfepy/fem/mesh.py
support mat_ids in merge_mesh()
new Mesh.__add__() to merge meshes
add verbose argument to MyBar progress bar
add verbose argument to gen_block_mesh(), gen_cylinder_mesh()