Add support for category tabs in 3D view's tool shelf, define new "MMD" category.
Merge pull request #19 from iRi-E/master

Add support for category tabs in 3D view's tool shelf.
Add "MMD Tools" category to the panel classes.
UI調整
Fix button layout of the panel.
PMX importer: Don't use alpha channel of sphere texture.
Follow up to previous commit: Avoid error when failing to load sphere texture.
Avoid error that occurs in Blender built without OpenColorIO.
Merge branch 'master' into 0.5.0-dev

Conflicts:
	mmd_tools/__init__.py
	mmd_tools/cycles_converter.py
	mmd_tools/import_pmx.py
Merge pull request #20 from iRi-E/fix_issues

Fix some issues
Merge branch 'master' into 0.5.0-dev

Conflicts:
	mmd_tools/__init__.py
CreateMMDModel時に特殊表示枠"Root", "表情"を追加するよう修正
Merge branch '0.5.0-dev' of https://github.com/sugiany/blender_mmd_tools into 0.5.0-dev

Conflicts:
	mmd_tools/cycles_converter.py
	mmd_tools/import_pmx.py
	mmd_tools/operators.py
	mmd_tools/panels.py