Update TargetPlatform Enum

Currently our ofTargetPlatformEnum is:

enum ofTargetPlatform{
    OF_TARGET_OSX,
    OF_TARGET_WINGCC,
    OF_TARGET_WINVS,
    OF_TARGET_IOS,
    OF_TARGET_ANDROID,
    OF_TARGET_LINUX,
    OF_TARGET_LINUX64,
    OF_TARGET_LINUXARMV6L, // arm v6 little endian
    OF_TARGET_LINUXARMV7L, // arm v7 little endian
    OF_TARGET_EMSCRIPTEN
};

For projects like Project Generator and ofSketch, it would be very useful to have a better differentiation for android, and 32/64 bit platforms. Proposed update:

enum ofTargetPlatform{
    OF_TARGET_OSX,   ///< 32 bit.
    OF_TARGET_OSX64,
    OF_TARGET_WINGCC, ///< 32 bit.
    OF_TARGET_WINGCC64,
    OF_TARGET_WINVS, ///< 32 bit.
    OF_TARGET_WINVS64,
    OF_TARGET_IOSARM64,
    OF_TARGET_IOSARMV7, ///< 32 bit.
    OF_TARGET_ANDROIDARMV5, ///< 32 bit.
    OF_TARGET_ANDROIDARMV7, ///< 32 bit.
    OF_TARGET_LINUX, ///< 32 bit.
    OF_TARGET_LINUX64,
    OF_TARGET_LINUXARMV6L, // arm v6 little endian ///< 32 bit.
    OF_TARGET_LINUXARMV7L, // arm v7 little endian ///< 32 bit.
    OF_TARGET_EMSCRIPTEN 
};

Alternatively it might be useful to break this down a bit:

enum ofTargetPlatform {
    OSX,
    WINGCC,
    WINVS,
    IOS,
    ANDROID,
    LINUX,
    EMSCRIPTEN
};

enum ofTargetArch {
    I386,
    X86_64,
    ARM5,
    ARM6,
    ARMV7,
    ARM64,
    NONE ///< Emscripten?
};

EDITED: to update w/ @danoli3's comments.

@danoli3 -- does that look right for IOS?
@arturoc What do you think?

Start by tracing how the ofTargetPlatform enum is consumed by Project Generator and ofSketch, then compare the existing platform and architecture assumptions with the alternatives in the issue. Done means the project consistently represents the required Android and 32/64-bit distinctions, with all affected consumers updated; the issue names no specific files or tests.