Add initial CMake support

* Support for both in-source and out-of-source builds
 * Set library version to 0.12 to map Debian package
 * Add separate options to build tests, examples and documentation
 * Add pkgconfig lookup support (if installed with `make install`)
 * Add CMake lookup support (if isntalled with `make install`)
 * Add Google Test Source lookup
 * Add CTest support for running tests (use `make test` or `ctest -V`)

example/CMakeLists.txt

@@ -0,0 +1,19 @@
+# Copyright (c) 2011 Milo Yip (miloyip@gmail.com)
+# Copyright (c) 2013 Rafal Jeczalik (rjeczalik@gmail.com)
+# Distributed under the MIT License (see license.txt file)
+
+set(EXAMPLES
+    capitalize
+    condense
+    messagereader
+    pretty
+    prettyauto
+    serialize
+    simpledom
+    simplereader
+    simplewriter
+    tutorial)
+
+foreach (example ${EXAMPLES})
+    add_executable(${example}_ ${example}/${example}.cpp)
+endforeach()