feat(simple-bmc): init code
src(tools/icp_vis): remove basic/error.ml
refactor(dsolvers/icp_solver): cleanup callODESolver
feat(dsolvers/util/logger): change default verbosity level to INFO
fix(src/type.ml): remove unnecessary field access function

remove functions(varmap, modemap, init_id, etc), they are not necessary.
fix(src/type.ml): remove unnecessary field access function