Refactor code.
Add a feature of exporting vertex weights.
Change to export texture paths as relative paths.
Change to ignore shadow bones.
Export is now faster.
Add the feature of exporting shape keys.
add the export pmx button.
Enhance the log.
Fix the bug that causes export errors of materials that have no texture.
Add support for IK into the export pmx feature.
Add support for an object that has no shape keys.
Change labels of buttons and checkboxes.
Merge branch 'master' into exporting_pmx

Conflicts:
	mmd_tools/__init__.py
Add support for some properties of pmx bones.
Merge branch 'master' into exporting_pmx

Conflicts:
	mmd_tools/__init__.py
Add support for toon textures
Add support for importing sphere maps.
Add support for importing some properties of materials.
Add a "MMD Material Tool Panel".
Add support for sphere textures.