removing old 'Run Script' steps needed for Xcode 4 unit testing.
dont_clang_as_osx: fix the issue where Xcode couldn't discover stuff.

This fixes the problem we were seeing in build.sh:

```
2013-11-01 14:10:35.062 xcodebuild[24282:4f1b] error: Error Domain=NSPOSIXErrorDomain Code=2 "Non-zero exit code 1 returned from shell command:
/Users/fpotter/xctool/otest-query/../Configurations/dont_clang_as_osx.py -v -E -dM -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -x objective-c -c /dev/null 2>&1" UserInfo=0x7fd59006d5c0
{NSLocalizedDescription=Non-zero exit code 1 returned from shell
command: /Users/fpotter/xctool/otest-query/../Configurations/dont_clang_as_osx.py -v -E -dM -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -x objective-c -c /dev/null 2>&1, NSLocalizedFailureReason=No such file
or directory}
2013-11-01 14:10:35.063 xcodebuild[24282:4f1b] Warning:  Couldn't discover the 'dont_clang_as_osx.py' compiler's built-in search paths and preprocessor definitions for language dialect 'objective-c'.
Compiler: /Users/fpotter/xctool/otest-query/../Configurations/dont_clang_as_osx.py
Reason: /Users/fpotter/xctool/otest-query/../Configurations/dont_clang_as_osx.py -v -E -dM -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -x objective-c -c /dev/null 2>&1
```
moving build scripts under a new 'scripts' dir.

I'm going to be adding to these, and don't want to clutter up the root
anymore.
link ROOT/xctool.sh -> ROOT/scripts/xctool.sh
scripts/build_settings.include generates the common build settings

We can then use this from build.sh and make_release.sh