Pre-release v4.0.0-rc2

• Refactored the helper package and split it into several focused packages.
  • helper/filesystem moved to util/fsutil
  • helper/walk moved to util/walk
  • New package util/httputil
    • Contains ParseMultiValuesHeader() and HeaderValue
  • New package util/reflectutil
    • Contains Only()
  • New package util/sliceutil
    • Contains IndexOf(), IndexOfStr(), Contains(), ContainsStr() and Equal() (previously named SliceEqual())
  • New pacakge util/sqlutil
    • Contains EscapeLike()
  • New package util/typeutil
    • Contains Map, ToFloat64(), ToString()

Motivation: The helper packaged started to become more and more bloated with functions for things unrelated to each other. To make this part of the code more idiomatic and expressive, the decision to split the package in several parts and re-think the naming was taken.

• The required rules now allows empty strings.
• Removed model:"hide" because it was redundant with json:"-".
• Added goyave.ProxyBaseURL() and server.proxy configuration entries.
• Added global middleware. Global middleware are executed on all requests, including requests that don't match any route or that result in "Method Not Allowed". This allows for better logging, rate limiting, and more, while keeping the already existing tools.