[BSP] fix compiling error for beaglebone board
Merge pull request #345 from aozima/pulls

update RW009 wifi driver.
Added Gitter badge
Update README.md
Merge pull request #348 from gitter-badger/gitter-badge

Add a Gitter chat badge to README.md
Update README.md
tools: preserve the order of CPPPATH/CPPDEFINES/LIBPATH/LIBS

The order of them are important while the uniqueness has nothing to do
with the compiling.
Merge pull request #349 from grissiom/fix-tools

tools: preserve the order of CPPPATH/CPPDEFINES/LIBPATH/LIBS
tools: fix SrcRemove on empty src

If the src is empty list, it will crash at:

    IndexError: list index out of range:
      File "/home/xxx/src/SConstruct", line 39:
        objs = PrepareBuilding(env, RTT_ROOT, has_libcpu=True)
      ...
      File "/home/xxx/src/drivers/SConscript", line 12:
        SrcRemove(src, src_need_remove)
      File "/home/rt-thread-stable/tools/building.py", line 496:
        if type(src[0]) == type('str'):
Merge pull request #351 from grissiom/fix-tools-srcremove

tools: fix SrcRemove on empty src
kernel/timer: change row_lvl to unsigned

Use signed int as array index is unsecure.
msh: check path is non-null in msh_auto_complete_path
msh: free is only available when HEAP is enabled
dfs: check for null reference
minilibc: only define malloc family when RT_USING_HEAP enabled
Merge pull request #353 from grissiom/misc-fix

Misc fix
Add mb9bf568r to bsp
Merge pull request #356 from yangfasheng/master

Add mb9bf568r to bsp
finsh: allow user to disable the FINSH_USING_HISTORY
Merge pull request #357 from grissiom/enhance-finsh

finsh: allow user to disable the FINSH_USING_HISTORY