Fix paths in pkg-config file (#556)

pkg-config should be giving absolute paths rather than relative paths.

README.md

@@ -44,7 +44,7 @@ cmake [-G generator] [-DBUILD_SHARED_LIBS=ON|OFF] ..
 
 # Recent Release #
 
-[yaml-cpp 0.5.3](https://github.com/jbeder/yaml-cpp/releases/tag/release-0.5.3) has been released! This is a bug fix release. It also will be the last release that uses Boost; futures releases will require C++11 instead.
+[yaml-cpp 0.6.0](https://github.com/jbeder/yaml-cpp/releases/tag/yaml-cpp-0.6.0) has been released! This release requires C++11, and no longer depends on Boost.
 
 [yaml-cpp 0.3.0](https://github.com/jbeder/yaml-cpp/releases/tag/release-0.3.0) is still available if you want the old API.
 

yaml-cpp.pc.cmake

@@ -1,5 +1,7 @@
-libdir=@LIB_INSTALL_DIR@
-includedir=@INCLUDE_INSTALL_ROOT_DIR@
+prefix=@CMAKE_INSTALL_PREFIX@
+exec_prefix=${prefix}
+includedir=${prefix}/@INCLUDE_INSTALL_ROOT_DIR@
+libdir=${exec_prefix}/@LIB_INSTALL_DIR@
 
 Name: Yaml-cpp
 Description: A YAML parser and emitter for C++