Tweak how tronview displays jobs

[mtytel]

• Give an option for how many job runs to display
• Display newer job runs first
• Multiple letter statuses to avoid ambiguity

[mtytel]

Here are some more changes:

• Show scheduled time
  
• If job follows another job, show that job instead of "Schedule: None"

[mtytel]

tronview now has three tiers of viewing.

• All jobs
• All job runs for a specific jobs
• All actions for a specific job run