Implemented run()
added addTask() method to TaskManager and inplemented it in ExecutorImpl
Updated ExecutorImpl
Updated TaskManager.java
Fixed problem where TaskManager instantiated as Runnable
Added size getter to TaskManager and another method in ExecutorImpl to get the return value of the getter
Added size getter to TaskManager and another method in ExecutorImpl to get the return value of the getter
changed size getter in ExecutorImpl to method to calculate max pending time
Added while(true) to TaskManager
Added shutdown method to TaskManager and ExecutorImpl
Some files from day18 I forgot to commit...