1. Add bsp stm32l452-st-nucleo.

2. Bsp stm32l452-st-nucleo has been tested with NUCLEO-L452RE board.
3. Modify the applications SConscript of bsp stm32f103-yf-ufun, using new method.
4. Modify README of bsp stm32f072-st-nucleo.

Author: lhxzui

bsp/stm32/stm32f072-st-nucleo/README.md

@@ -2,7 +2,7 @@
 
 ## 简介
 
-本文档为刘恒为 NUCLEO-F072RB 开发板的 BSP (板级支持包) 说明。
+本文档为刘恒为 NUCLEO-F072RB 开发板提供的 BSP (板级支持包) 说明。
 
 主要内容如下：
 

bsp/stm32/stm32f103-yf-ufun/applications/SConscript

@@ -1,10 +1,8 @@
-Import('RTT_ROOT')
-Import('rtconfig')
 from building import *
 
 cwd = GetCurrentDir()
-src = Glob('*.c')
-CPPPATH = [cwd, str(Dir('#'))]
+src = Glob('*.c') + Glob('*.cpp')
+CPPPATH = [cwd]
 
 group = DefineGroup('Applications', src, depend = [''], CPPPATH = CPPPATH)