Remove custom test VM setup

We now use Travis CI again, so our VM becomes superfluous.

Makefile

@@ -1,7 +1,6 @@
 EMACS = emacs
 EMACSFLAGS =
 CASK = cask
-VAGRANT = vagrant
 SPHINX-BUILD = sphinx-build
 INSTALL-INFO = install-info
 INSTALL = install
@@ -13,7 +12,6 @@ export EMACS
 
 SRCS = flycheck.el
 OBJECTS = $(SRCS:.el=.elc)
-HOOKS = .git/hooks/pre-push
 
 DISTDIR = dist
 BUILDDIR = build
@@ -22,8 +20,8 @@ DOCTREEDIR = $(DOCBUILDDIR)/doctrees
 
 .PHONY: compile dist doc html texinfo \
 	clean clean-elc clean-dist clean-doc clean-deps \
-	test vagrant-test \
-	deps linkcheck hooks
+	test \
+	deps linkcheck
 
 # Build targets
 compile : $(OBJECTS)
@@ -42,18 +40,12 @@ texinfo : doc/flycheck.texi
 test : compile
 	$(CASK) exec ert-runner
 
-vagrant-test :
-	$(VAGRANT) up --provision
-	$(VAGRANT) ssh -c "make -C /flycheck EMACS=$(EMACS) clean-elc test"
-
 # Support targets
 deps : $(PKGDIR)
 
 linkcheck :
 	$(SPHINX-BUILD) -b linkcheck -n -d $(DOCTREEDIR) doc $(DOCBUILDDIR)/linkcheck
 
-hooks: $(HOOKS)
-
 # Cleanup targets
 clean : clean-elc clean-dist clean-deps clean-doc
 
@@ -69,10 +61,6 @@ clean-doc:
 clean-deps :
 	rm -rf $(PKGDIR)
 
-# File targets
-.git/hooks:
-	install -d $@
-
 $(PKGDIR) : Cask
 	$(CASK) install
 	touch $(PKGDIR)

doc/flycheck-versus-flymake.rst

@@ -429,11 +429,7 @@ Unit tests
 
 **Flycheck** has unit tests for all built-in syntax checkers, and for large
 parts of the underlying machinery and API.  Contributed syntax checkers are
-required to have test cases.
-
-A virtual machine specification based on Vagrant_ and Puppet_ is provided to
-setup a complete testing environment with all supported syntax checker tools and
-Emacs versions, plus necessary utilities.
+required to have test cases.  The tests are continuously run on `Travis CI`_.
 
 .. [#] Flycheck is **unlikely to ever become part of Emacs**.
 .. [#] The 3rd party library flymake-easy_ allows to use syntax checkers per
@@ -464,3 +460,4 @@ Emacs versions, plus necessary utilities.
 .. _Puppet: http://puppetlabs.com/
 .. _MELPA: http://melpa.milkbox.net/
 .. _Github: https://github.com/flycheck/flycheck
+.. _Travis CI: https://travis-ci.org/flycheck/flycheck