Build the nif file tester by default

It's extremely useful in determining if a nif file is bad without having to load up openmw or opencs.
Also updated the nif testing script to run at a low priority.

CMakeLists.txt

@@ -82,7 +82,7 @@ option(BUILD_OPENCS "build OpenMW Construction Set" ON)
 option(BUILD_WIZARD "build Installation Wizard" ON)
 option(BUILD_WITH_CODE_COVERAGE "Enable code coverage with gconv" OFF)
 option(BUILD_UNITTESTS "Enable Unittests with Google C++ Unittest and GMock frameworks" OFF)
-option(BUILD_NIFTEST "build nif file tester" OFF)
+option(BUILD_NIFTEST "build nif file tester" ON)
 option(BUILD_MYGUI_PLUGIN "build MyGUI plugin for OpenMW resources, to use with MyGUI tools" ON)
 
 # OS X deployment

components/nif/tests/test.sh

@@ -9,7 +9,7 @@ find "$DATAFILESDIR" -iname *nif >> nifs.txt
 
 sed -e 's/.*/\"&\"/' nifs.txt > quoted_nifs.txt
 
-xargs --arg-file=quoted_nifs.txt ../../../niftest
+nice -n 10 xargs --arg-file=quoted_nifs.txt ../../../niftest
 
 rm nifs.txt
 rm quoted_nifs.txt