memheap: dont 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.
Merge pull request #131 from grissiom/memheap

memheap: don't alloc/memcpy when there is next node is enough for realloc
SEP6200 Support
Cleanup and add licencse
update AT91SAM9260 usart driver， using serial driver component.
update at91sam9260 project directory structure.
commit again
fix compiling error
Embedded GPLv2 license.
Merge pull request #133 from weety/at91sam9260

At91sam9260
add mount table
simulator: update to support simulator for linux
Merge pull request #134 from prife/sim-fix

simulator: update to support simulator for linux
add initialization debug code
Merge branch 'master' of https://github.com/RT-Thread/rt-thread
modify codes for fractional divider
add NRZ feature on K60
fix a bug in rt_hw_uart_init() where u CAN NOT init some feature.
delete K60.pro
remove a var for INT_TX.