Support for Portamento and Pitch Bender parameters (probonopd#206) Thanks @arsamus

Next try for ReverbMixer and NEON extensions (RPi2/3/4) (probonopd#86) * Signal chain is now float32_t with much more support of CMSIS5. * Fixes for float signal path. * Several fixes for float signal path. * Manual merge of changes from upstream. * Fixes for wrong panning calculation. * Added code for master compressor. Added code for mixer. Added HAVE_NEON to MAkefile for enabling more optimizations on Synth_Dexed. * Adding mixer class - but it has some linking problems... * Fast fix. * Next fast fix. * Fixing effect_mixer. * Added ReverbSend Parameter for each TG. * Fixes for ReverbSend and Pan. * Fixing constrain(). * Fix aarch64 build, thanks @rsta2 probonopd#85 (comment) * Fix for building for RPi1. * Add TGParameterReverbSend probonopd#86 (comment) Thanks @rsta2 * Add TGParameterReverbSend probonopd#86 (comment) Thanks @rsta2 * Implement changes suggested by @rsta2 Description: probonopd#86 (comment) Thanks @rsta2 Co-authored-by: Holger Wirtz <wirtz@parasitstudio.de> Co-authored-by: probonopd <probonopd@users.noreply.github.com>

Added support for CMSIS_5, so upstream Synth_Dexed can be used (probo… …nopd#41) * Fixes for using standard Synth_Dexed. Added support for CMSIS. * Fix for branch of Synth_Dexed * Submodules for Synth_Dexed and CMSIS_5 added. Co-authored-by: Holger Wirtz <wirtz@parasitstudio.de>

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