Plugin name must be a valid C++ identifier

[Albert Graef]

At present, the basename of the dsp source is used for a bunch of different identifiers needed when generating the LV2 bundle, and one of these is the dsp class name, so it must be a valid C++ identifier. This means that compilation with the provided Makefiles and build scripts with fail if the dsp filename contains punctuation or blanks.

To fix this, the dsp class name should be handled separately from the other plugin identifiers used for the plugin dll, uri etc. The architecture files, manifest templates, Makefiles and build scripts will have to be revised accordingly.