Rename project in CMake

TODO: to create symlinks to the old names!
diff --git a/include/CMakeLists.txt b/include/CMakeLists.txt
index 17a098c..2c56858 100644
--- a/include/CMakeLists.txt
+++ b/include/CMakeLists.txt
@@ -1,6 +1,6 @@
-option(INSTALL_POLARSSL_HEADERS "Install mbed TLS headers." ON)
+option(INSTALL_MBEDTLS_HEADERS "Install mbed TLS headers." ON)
 
-if(INSTALL_POLARSSL_HEADERS)
+if(INSTALL_MBEDTLS_HEADERS)
 
 file(GLOB headers "polarssl/*.h")
 
@@ -8,4 +8,4 @@
         DESTINATION include/polarssl
         PERMISSIONS OWNER_READ OWNER_WRITE GROUP_READ WORLD_READ)
 
-endif(INSTALL_POLARSSL_HEADERS)
+endif(INSTALL_MBEDTLS_HEADERS)