Misc fix

ARMCC will define __GNUC__ in "GNU mode"(with --gnu command line
option). So iff __GNUC__ && !__CC_ARM is GCC.

There is no list_mem and only list_memheap when RT_USING_MEMHEAP_AS_HEAP
is enabled.

Add uart driver and finsh function

[BSP] Port to NuMicro M051 Series support for Nuvoton corp and fix compile warning

    1. adapt to M052xDN/xDE, M054xDN/xDE, M058xDN/xDE, M0516/xDN/xDE.
    2. support heap memory management.

Fix compile warning: variable "c" was declared but never referenced, when RT_USING_CONSOLE is disable.

Add mdk5 building

efm32: return empty variable instead of Return('')

SCons: allow set object files in DefineGroup

The source files can be the raw file names end with .c or .o. So return
the raw file names is more flexible than wrap them with Object.

update RW009 driver: add softAP support.

add a support for rx62n

update the change logs

modified the comments of block device geometry structure, to tell everyone the unit of block_size is byte.

bsp:fix the bug of lpc43xx uart interrupt enable in driver initialize.

romfs: fix a use-before-set bug on checking the dirent

[BSP] Add GCC compiler support for mb9bf568r

ymodem: fix examples due to new API

Romfs next

System will crash when the romfs is erased. Add checks before using them
to avoid it.