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.
doc(README.md): add pkg-config

[skip ci]
doc(ubuntu-gcc.md): add pkg-config

[skip ci]
doc(ubuntu-clang.md): add pkg-config

[skip ci]
src(tools/simple-bmc): add Makefile, update _tags
src(tools/simple-bmc): add Integral and Vec to exp, simplify code
src(tools/simple-bmc): update Define-ODE to take a set of ODEs
src(tools/simple-bmc): use new define-ODE and produce flow formula(integral)
fix(tools/simple-bmc): update makefile