add signin action into explorer title (LeetCode-OpenSource#42)

prepare for 0.6.0 release

refine changelog

prepare for 0.5.0 release(LeetCode-OpenSource#33)

change the place of the lock decorator (LeetCode-OpenSource#23)

support test solution (LeetCode-OpenSource#16)

* support test solution

* escape the line seperator

* update readme