Support python3.6 and 2.7

Change method name macaron.create_link_table() -> macaron.create_link…

…_tables()

After this commit, version is up to 0.4.0-dev.

Modify webapp.rst and setup.py. Release 0.3.1.

MODIFY: Release number

Some documents are modified to be suitable for current release. Relea…

…se 0.2.0

Release 0.2.0

MODIFY: Document and 0.1.0 release