Add vcpkg installation instructions

[PhoebeHui]

Hi Cello team,

Cello is available as a port in vcpkg, a C++ library manager that simplifies installation for Cello and other project dependencies. Documenting the install process here will help users get started by providing a single set of commands to build Cello, ready to be included in their projects.

We also test whether our library ports build in various configurations (dynamic, static) on various platforms (OSX, Linux, Windows: x86, x64) to keep a wide coverage for users.

I'm a maintainer for vcpkg, and here is what the port script looks like We try to keep the library maintained as close as possible to the original library.

I try to add vcpkg installation instructions but I couldn't find the related docs in github except for on http://libcello.org/learn/installation page.

Could you please help add the following contents to this port?

Installing and building Cello via vcpkg

You can download and install Cello using the vcpkg dependency manager:

  git clone https://github.com/Microsoft/vcpkg.git
  cd vcpkg
  ./bootstrap-vcpkg.sh
  ./vcpkg integrate install
  vcpkg install cello

The cello port in vcpkg is kept up to date by Microsoft team members and community contributors. If the version is out of date, please create an issue or pull request on the vcpkg repository.