Merge branch 'build_cmake' of https://github.com/TcT2k/wxWidgets

Add CMake-based build system.

Merge the original branch without any changes except for resolving the
conflict due to moving the contents of .travis.yml to a separate file by
propagating the changes done in this file since then to the new script
and rerunning ./build/update-setup-h and ./build/cmake/update_files.py
to update the file lists changed in the meanwhile.

Closes https://github.com/wxWidgets/wxWidgets/pull/330

build/cmake/samples/html.cmake

@@ -0,0 +1,42 @@
+#############################################################################
+# Name:        build/cmake/samples/html.cmake
+# Purpose:     CMake script to build html samples
+# Author:      Tobias Taschner
+# Created:     2016-10-22
+# Copyright:   (c) 2016 wxWidgets development team
+# Licence:     wxWindows licence
+#############################################################################
+
+set(wxSAMPLE_FOLDER html)
+set(wxSAMPLE_SUBDIR html/)
+
+wx_add_sample(about DATA data/about.htm data/logo.png LIBRARIES html)
+wx_list_add_prefix(HELP_DATA_FILES helpfiles/
+    Index.hhk
+    another.hhc
+    another.hhp
+    another.htm
+    book1.htm
+    book2.htm
+    contents.hhc
+    main.htm
+    page2-b.htm
+    testing.hhp
+    )
+wx_add_sample(help DATA ${HELP_DATA_FILES} LIBRARIES html NAME htmlhelp)
+wx_add_sample(helpview DATA test.zip LIBRARIES html)
+#TODO: htmlctrl sample uses outdated definitions
+#wx_add_sample(htmlctrl LIBRARIES html)
+wx_add_sample(printing DATA logo6.gif test.htm LIBRARIES html NAME htmlprinting)
+wx_add_sample(test
+    DATA
+        imagemap.png pic.png pic2.bmp i18n.gif
+        imagemap.htm tables.htm test.htm listtest.htm 8859_2.htm cp1250.htm
+        regres.htm foo.png subsup.html
+    LIBRARIES net html NAME htmltest)
+wx_add_sample(virtual DATA start.htm LIBRARIES html)
+wx_add_sample(widget DATA start.htm LIBRARIES html)
+wx_add_sample(zip DATA pages.zip start.htm LIBRARIES html)
+
+set(wxSAMPLE_SUBDIR)
+set(wxSAMPLE_FOLDER)