Perform init of CxxTest regardless of env CXXTEST

Perform init of CxxTest regardless of env CXXTEST
    initialize_project.sh
Added support Android runtime writeable files

Also:
 - Minor tools changes. Added target for running linux tests.
 - Added CxxTest path to -isystem, for when building tests on linux with a
   manually created CxxTest runner file (like the one generated for executing
   tests on android)

    common_build.py
    devtools.sh

Android can now write log to file, same as on desktop.
The macro LOG2FILE_DISABLED is no longer set.
    src/Android.mk

File classes now differentiate between Asset filetypes and Writeable files.
Tests have been changed accordingly, and most also pass on Android.

    src/util/File.cpp
    src/util/File.h
    src/util/FileMonitor.cpp
    src/util/FileMonitor.h
    src/util/FileUtil.cpp
    src/util/FileUtil.h
    src/util/LogManager.cpp
    src/util/LogManager.h
    src/util/TestAsset.h
    src/util/TestFile.h
    src/util/TestFileMonitor.h
    src/util/TestFileUtil.h
    src/util/TestLog.h
    src/util/TestLogManager.h
    src/util/TestObjUtil.h