Second Prototype (SMD version)

Major fixes to the muting mechanism, rework as SMD and tweaked component choices.

What's Changed

• Re-layout boards with SMD components by @jbeyerstedt in #4
• Fixes to SMD re-design: Added ground lift, fixed caps and mic gain LP filter by @jbeyerstedt in #6
• Rework of channel muting, tweak potentiometer values by @jbeyerstedt in #5
• Final fixes before production by @jbeyerstedt in #7

Full Changelog: v0.2.1...v0.3.3