LeoCAD 21.06

• Synthesize Technic Pneumatic Tubes
• Added option to choose the axis icon location.
• Added LeoCAD to the Linux Snap Store.
• Added preview indicator for synth parts.
• Fixed crash loading certain parts.
• Fixed moving pieces while editing submodels in place.
• Fixed loading primitives from ldrawunf.zip.
• Made library installation optional in the Windows installer.
• Highlight missing parts in the timeline.
• Add Unhide selected menu item