Support uloop(from OpenWrt libubox) reactor; GC bug fixed; Support choose the reactor.

Signed-off-by: Xiongfei(Alex) Guo <xfguo@credosemi.com>
[WIP] travis-ci debug.

Signed-off-by: Xiongfei(Alex) Guo <xfguo@credosemi.com>
[WIP] travis-ci debug.

Signed-off-by: Xiongfei(Alex) Guo <xfguo@credosemi.com>
[WIP] travis-ci debug.

Signed-off-by: Xiongfei(Alex) Guo <xfguo@credosemi.com>
[WIP] Add cancel OP for reactor; Check the num of actors; travis-ci deubg.

Signed-off-by: Xiongfei(Alex) Guo <xfguo@credosemi.com>
Merge pull request #1 from xfguo/reactor-uloop

Support uloop(from OpenWrt) based reactor; Scheduler support choose reactor; Reactor support cancel loop.