QP/C++ 5.4.1 released

QP/C++ version 5.4.1 changes the active object class hierarchy so that QMActive is now more fundamental and is the base class for QActive. (Previously QMActive was a subclass of QActive). The newly added documentation section about QP/C++ Design shows the current class hierarchy.

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NOTE: Because the types QMActive and QActive are equivalent in QP/C++, this change has minimal impact on the applications, but it is now more correct to use QMActive as the base class for all "opaque" active object pointers.

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Also, this release brings several cosmetic improvements:

1. All QM models have been saved with QM 3.3.0, which means that they will not open with QM 3.2.x or earlier QM versions.

2. The qpcpp/ports/arm-cm/qk/gnu/qk_port.s ARM Cortex-M port to QK with GNU has been modified to use the CMSIS-compliant symbol __FPU_PRESENT instead of the FPU_VFP_V4_SP_D16 symbol.

3. All Makefiles for the GNU toolset have been cleaned up, whereas any \ (back-slash) characters in the paths have been repalced with / (forward-slash) characters. Also all these Makefiles have been updated to provide the __FPU_PRESENT to C/C++ and assembler when the hardware FPU is used.

4. The file display drver for the EK-LM2S811 board locate at qpc/3rd_party/ek-lm3s811/display96x16x1.c has been modified to fix the problem with incorrect hardware delay with the GNU compiler at higher levels of optimization. The in-line assembly for the GNU compiler has been updated such that the delay loop cannot be "optimized away".

5. Several README files have been updated.