Fix warning from GCC

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>
Remove static_assert from rbtree, as it result in GCC compile error

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>
Fix undefined reference for GCC

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>
Add usage of system_timer in example

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>
Rename test files

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>
Add poll.cpp

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>
Extract poller

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>
Test behaviour of timer

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>
Change timer behaviour

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>
Add stop method to timer

Signed-off-by: LAN Xingcan <lanxingcan@gmail.com>