LSP Multiband Gate plugin series

LSP Plugins release : * Implemented Multiband Gate plugin series. * Added sidechain low-pass and high-pass filters for Compressor plugin series. * Added sidechain low-pass and high-pass filters for Expander plugin series. * Added sidechain low-pass and high-pass filters for Gate plugin series. * Added sidechain low-pass and high-pass filters for Dynamic Processor plugin series. * Added sidechain low-pass and high-pass filters for Trigger plugin series. * Fixed VST2 identifiers for Multiband Expander