pyeit-1.1.9: Generate realistic head and lung meshes!

What's Changed

• Improved f solver calculation by @ChabaneAmaury in https://github.com/liubenyuan/pyEIT/pull/37
• Optimize .et3 and .mes loading routine. Generate optimized thorax shape using distmesh and shapely by @liubenyuan in https://github.com/liubenyuan/pyEIT/pull/38
• Generate High quality Head (symmetric) and Lung meshes. e986162

Full Changelog: liubenyuan/pyEIT@v1.1.8...v1.1.9