API-ready changes made

CHANGES

• Separated index.js to index.js and cli.js
• Changed gentest command to run ./cli.js instead of ./index.js
• Removed unused -F (forcePrint) option from ./cli.js
• Removed unused -m (method) option from ./cli.js
• Changed test.js to run cli.js instead of ./index.js
• Changed index.js to return string instead of writing to any file

BREAKING CHANGES

• -F --forcePrint option is removed for simplicity
• -m --method option is removed for simplicity
• directory-level test file generation is NOT available
  • includeMatch option for config is removed
  • excludeMatch option for config is removed