IMPROVEMENTS:

• Add more upfront validations #170.
• Add field backup_retention to MS SQL server backup #170.
• Add field host to PaaS resource and PaaS-type resources (e.g. postgres, MySQL, etc.) #169.

FEATURES:

• Add MySQL resource #166.
• Add Memcached resource #167.
• Add Redis store/cache resources #168.

BUG FIXES:

• Fix MS SQL server backup's params cannot be updated #170.