Migrating node-cron to TypeScript, grating native support when using it in typescript projects.

fixes:

• step values, 1-59/2 should match 1,3,5,7... (Bug Report: Incorrect Execution of 0 0 1 */3 * Schedule #435, Job not running at full hours with expression */15 * * * * #260, Job running at wrong time with '1-59/3 * * * *' #282, jobs are not execution in odd number minute and hours  #201)
• fixed task controls, and making it available inside the task. (task.stop() Not Working #317 )

features:

• max executions, allows a job execute at max defined on scheduling (Request: schedule one time job #249)
• getTasks: returning all scheduled tasks.
• destroy: stop a job and release it.