Fixes to make CasADi importable from external SWIG modules again

* Wrap some traits/fragments with `#idef CASADI_MODULE` to avoid leakage into
  code that SWIG generates for other modules.
* Specify the package of all CasADi modules since they now reside in the
  `casadi` package in Python. Otherwise, e.g. `%import "casadi_core.i"` will
  always emit an unqualified `import casadi_core` line into the generated
  Python wrappers. Now it becomes `import casadi.casadi_core` instead.
#1222 Speed up unittests
Plugin_interface: avoid avoid code duplication
LyapSolver overhaul: struct schemes for Dple/Dle
Added low rank base class LrDple/LrDle
Added Smith implementation, lifting, condensing
Added many unittests
Fixing make lint, make spell (targets were missing)
Fixes to previous commit
Fixes to previous commit (lint)
Fixes to previous commit (lint)
Fixes to previous commit (adaptors went missing)
Patching some Lyap unittests
automatic documentation update
Merge pull request #1223 from toivoh/module_compatible4

Fixes to make CasADi importable from external SWIG modules again
automatic documentation update
automatic casadibot merge