Add OPAM 1.2 into the testing mix
improve atdgen descr
Fix travis matrix for all combos
experiment with travis matrix to get less osx
Revert "experiment with travis matrix to get less osx"

This reverts commit 9ba284647fef8193e33c890a2ea1a6f2fad02b4d.
Attempt another way to exclude osx builds
travis; fix support matrix
fix ocaml 4.02 ppas
4.02 is now a system switch, no need to build it separately
Add a system variant of camlp4 that is a dummy package that checks
for the existence of a system installation of camlp4 if the compiler
is a 4.02 system compiler.

Add the converse relation to the non-system 4.02.0 package (which
should only be used in a custom switch)
Merge branch 'opam-1.2' of github.com:avsm/opam-repository into opam-1.2
fix osx travis switches
Fix available syntax on OPAM 1.1.x, via @samoht
Set OPAMSTRICT when testing packages
Further tweak the syntax to be OPAM 1.1 compatible and add installation help
Preinstalled needs to be a string, not bool
Attempt another permutation of preinstalled syntax
Another variant of preinstalled syntax from @samoht
typo: camlp4.4.02.0+system should be preinstalled
correct osx 4.02 switch