v0.0.20: Merge pull request #33 from BetterCallSky/refactor-optional

Changes since 0.0.19:

• Big change in API - removal of optionalType(), from now on schema properties are optional by default, required types needs declaration inside options object, just like in mongoose (for example: Type.string({ required: true }))
• Decimal128 support added
• Added ExtractFromReq which takes extracted props and convert them into simple types - that might be useful if you are using same interfaces on FE and BE and send data as JSON
• Support for following schema options:
  • timestamps, might be declared as simple boolean, boolean for each option or readonly string for each option
  • versionKey - can be declared as boolean or readonly string
• fixes:
  • statics - it's done in different way but should work correctly, take a look at readme
  • optional fields are now represented as Type | undefined not Type | null | undefined
  • fix for array of subSchemas