Merge pull request #53 from shengwen1997/master

Support print out the unsaved settings (Status Monitor)
Let read sd card faster than previous version
Change task communication mechanism
sdsave could work very well now
Merge branch 'master' of https://github.com/fboris/QuadcopterFlightControl

Conflicts:
	program/shell/shell.c
	program/system/main.c
Cast uint64_t to int
Because our printf could not support uint64_t, we solved it by casting uint64_t
to int
Add SDcondition and linenoise in the sdio.c. Update sdsave command.

You can choose whether you want to store or not.
Merge pull request #2 from zxc2694/master

Add SDcondition and linenoise in the sdio.c.