tests(nra_ode): add fedor_01 and fedor_02
fix(src/CMakeLists.txt): add deps between GLOG and GFLAGS
fix(dsolvers/ode_solver): extract mode invariant

In case we have multiple invariants on a variable, we join the
constraints. Previously, we just take the latest one in the stack.

Closes #49.
fix(src/CMakeLists.txt): suppress warnings from capd and glog
tests(nra_ode): add expected results for fedor_01 and fedor_02
fix(src/CMakeLists.txt): suppress warnings from libunwind
checkpoint - new_realpaver
fix comment
checkpoint
fix interval
checkpoint