C code generator should allow to suppress generation of sc_types.h

[nyssen]

If generating multiple statecharts, sc_types.h gets generated multiple times. However, its contents is not dynamical w.r.t. to the concrete state machine, thus it would suffice to have it generated only once (to be specified via a genmodel parameter). It would also be helpful if the generation path for this file could be individually specified via a genmodel parameter in addition.

[nyssen]

Alternatively it would be ok to specify a distinct output path for the static code parts (up to now only sc_types.h).

[nyssen]

I implemented general support for all code generators to specify a distinct output location for static (i.e. model independent) code. That is, the Outlet feature now provides support for an optional libraryTargetFolder and the C and Java code generators are adopted to evaluate this and generate their static code artifacts into the respective location. In contract to the default targetFolder, the libraryTargetFolder will not be overwritten or cleaned, so that manual adoptions can be made. Closing because all changes have been pulled into master.