memheap: don't alloc/memcpy when there is next node is enough for realloc

When realloc a bigger space and the next node is free and big enough, we
should directly relocate the next node instead of doing alloc/memcpy.
The new method not only faster in this cases, it would avoid memory
fragment as well.

update stm32f10x.

fix compiling error in Linux.

simulator: update code for new component initialization support on mingw

update linker script and SConstruct.

add K60Fxxxx bsp for TWR-K60F120M board.

Remove initialization feature for MS VC++ compiler.

enhancement hard fault exception handler.

building.py: add clang static analyzer support

device: add ref_count support

It adds the '--clang-analyzer' option that could invoke clang as the
static code checker. It is recommanded to work with 'scan-build' shipped
with Clang. For example, `scan-build scons --clang-analyzer`.

This is a simple work around to the current device stack design. A
ref_count could let different modules to open/close the same device
independently without interfere others in some degree.

But there is still some data shared between the modules, like flag,
open_flag and user_data. Moreover, it won't yield an error if A open a
device, and B read from it before open it in B. Maybe alloc a new handle
in rt_device_open will be the ultimate solution. But that is much bigger
change and we may leave it to future development.

dfs: fix the variable definition bug in copy, found by ffgamelife from rt-thread.org

remove RT_LWIP_TCP_SND_BUF setting