3.0.0

This release contains major feature improvements and bugfixes.

• feat: support multiple style declarations in same file
• feat: support inline <style> tags in custom RexExp
• feat: styleDelineator option allows users to specify the delineator for style declarations
• feat: env option allows users to specify environment via rollup.config.js, not just NODE_ENV
• feat: configPath options allows users to configure the path/to/postcss.config.js
• fix: support Function and Object exported from postcss.config.js
• fix: use process.cwd() instead of __dirname to find postcss.config.js
• fix: document missing options in README.md