message: * Fixed 404 links in docs
diff: ## Building of Indy SDK
  -* [Ubuntu based distro (Ubuntu 16.04)](docs/windows-build.md)
  -* [RHEL based distro (Amazon Linux 2017.03)](docs/rhel-build.md)
  -* [Windows](docs/windows-build.md)
  -* [iOS](ios/ios-build.md)
  \ No newline at end of file
  +* [Ubuntu based distro (Ubuntu 16.04)](doc/ubuntu-build.md)
  +* [RHEL based distro (Amazon Linux 2017.03)](doc/rhel-build.md)
  +* [Windows](doc/windows-build.md)
  +* [iOS](doc/ios-build.md)
  \ No newline at end of file
  