1) Added doxygen tags to SafeC header comments.

The following tags were used:
* @brief: Tells in brief the functionality of functionality.
* @details: Tells complete description of the functionality.
* @param: Tells about the parameters used by function. [in] denotes parameter is an input & [out] denotes parameter is an output.
* @remark: Tells additional details about the function (E.g. Specified in/Extension to specific technical report)
* @return: Tells about what function returns.
* @retval: Tells about the return values.
 @code & @endcode: demonstarte sample code.

2) SYNCED parameter names of functions in mem_primitives_lib.c according
to parameter names used in function declaration in mem_primitives_lib.h.
The following function signatures we synced:
* mem_prim_set(): Parameter uint32_t len modified to uint32_t dmax.
* mem_prim_set16()/mem_prim_set32() : Parameters uint16_t *dp & uint32_t len were modified to uint16_t *dest & uint32_t dmax respectively.
* mem_prim_move(): Parameter uint32_t len modified to uint32_t length.
* mem_prim_move8() /mem_prim_move16() /mem_prim_move32() : Parameters uint32_t *dp, const uint32_t *sp & uint32_t len were modified to uint32_t *dest, const uint32_t *src & uint32_t length respectively.