Appveyor Level Up

[ForNeVeR]

• [x] build only RelWithDebInfo on Appveyor
• [x] pack it without PDB
• [x] pack PDBs into a separate archive
• [x] run ctest (ctest ., see on Travis)
• [x] publish Release to GitHub releases (see this as an example)

[berkus]

Latest developments:

• On Travis we are building only RelWithDebInfo build, lets do the same for AppVeyor.

(i.e. publish it too, but need to not package the PDB files to final distro zip)

[ForNeVeR]

@berkus why don't publish PDB?

[berkus]

I didn't say "don't publish"

I said not package it into the installer ZIP file.

Publish PDB as separate artifact for debugging.