issue #1687: Refactoring CCFileUtils, abstracting the same implementations for all platforms.
issue #1687: [Marmalade] If the font name wasn't end with `.ttf`, skip making a full path.
issue #1687: Comments some logs output for CCFileUtils.
issue #1687: Updating comments for CCFileUtils.
issue #1687: Updating the comments for CCFileUtils.
issue #1687: Updating the comments for CCFileUtils.
issue #1687: Moving the global function( ccFileUtils_dictionaryWithContentsOfFileThreadSafe,  ccFileUtils_arrayWithContentsOfFileThreadSafe) to the CCFileUtils class.
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issue #1687: Adding new test - Checking whether file exists.
issue #1687: CCFileUtils::isFileExist now support relative path.
issue #1687: Moving the implementation of NS2CC.mm to CCFileUtilsIOS(MAC).mm.
Merge pull request #1941 from dumganhar/iss1687-refactor

issue #1687: Refactoring CCFileUtils, abstracting the same implementations for all platforms.