Update default.xml

Commented Out (removed) line(s): #333, #345, #347 - 
<!-- <project path="prebuilts/gcc/linux-x86/arm/arm-eabi-4.6" name="platform/prebuilts/gcc/linux-x86/arm/arm-eabi-4.6" groups="linux,arm" /> -->
<!-- <project path="prebuilts/gcc/linux-x86/arm/arm-eabi-linaro-4.7" name="android_prebuilts_gcc_linux-x86_arm_arm-eabi-linaro-4.7" remote="andro" revision="jellybean" groups="linux,arm" /> -->
<!-- <project path="prebuilts/gcc/linux-x86/arm/arm-eabi-linaro-4.7" name="Andromadus/android_prebuilts_gcc_linux-x86_arm_arm-eabi-linaro-4.7" remote="github" revision="jellybean" /> -->