C API symbols should be prefixed

[0u812]

C APIs typically "solve" the namespace pollution problem by prefixing their functions and types with some epithet for the library. In our case it's rr. So, getNumRegisteredIntegrators becomes rr_getNumRegisteredIntegrators, simulate becomes rr_simulate. I suppose RRHandle can remain the same.

It's a shame this wasn't done already, mainly because we don't have much C expertise on the team. If a C programmer ever got hold of this code, they'd probably be offended by its namespace pollution. Every single symbol in the C API should be prefixed in some future release.

[0u812]

Just to state the obvious: this breaks backwards compatibility.

[hsauro]

Hence we cannot change it at the moment. We can revisit this in version 2.0
of libroadrunner. I need some stability at the moment in the API since its
been too fluid in the last few years.

[hsauro]

PS One possibilityis to create a parrallel API with the rr prefix and to
deprecate the non-rr api in version 2.0 of libroadrunner.