This PR places all LMMS symbols into namespaces to eliminate any potential future name collisions between LMMS and third-party modules.
Also, this PR changes back `LmmsCore` to `Engine`, reverting c519921306 .
Co-authored-by: allejok96 <allejok96@gmail.com>
No functional changes! No changes to savefiles/presets!
Fixes casing of everything that is currently lowercase but should
be uppercase.
Fixes also some other plugin strings, especially:
* opl2 -> OpulenZ (see 289887f4fc)
* calf -> veal (see ae291e0709)
* ladspa_effect -> LadspaEffect (see 9c9372f0c8)
* remove flp_import (see 2d1813fb64)