Updates to CI services

[guitorri]

Travis:

• move to a container based instance
• set to 2 cores
• evaluate the need of branches for coverage update, unstable tarballs and ftp to SF
• speedup OSX, create a homebrew cask for qt4 (including qt3support).
• setup qucs-doc (latex and what not)
• enable artifacts (associated with tags) for the make dist tarball.
• re-enable generation of Doxygen pages Re-enable CI build of Doxygen docs #724
• OSX, re-enable make qucsatorcheck Travis CI, random issues running qucs-test. #644

AppVeyor:

• add --disable-dependency-tracking to speedup the build
• enable qucs-test (install python and what not)
• set to 2 cores
• enable 32bit (64bit already set)
• enable packaging (even without qucs-doc) see [WIP] Use Appveyor to build 32 and 64 bit packages #561
• cleanup, create a generic .sh script so that any user can build with it.
• setup qucs-doc (latex) appveyor and check #468
• enable make check try to make check in appveyor #469

[guitorri]

Added a few more tasks to AppVeyor.

[felix-salfelder]

does it mean that travis actually supports "setup build environment once and just use it every time"?

(i was looking for something like it, but couldnt find)

[guitorri]

you mean the container based thing? I think so, you can reuse the build env. After you create the container, they keep the image around, so it is pretty quick to re-start it. I think it is based (or can be used as) Docker. I quickly read about it, I don't know exactly what needs to be done to activate.