History Limiter Custom

A personal edit of nschneirov's History Limiter put up to share. Overall the logic remain unchanged from the original version.

Main changes:

• code reworks to eliminate need for jQuery and to facilitate manifest ver 2
• event page enabled
• no changes to logic, no new functions

The main aim of this edit is to make it event page enabled so it unloads when not needed thus saving memory.

================= CHANGELOG:

1.2 [21/04/2018]

• back to using a set button to overcome the premature clear
• some minor UI changes

1.1.1 [10/05/2014]

• history will be trimmed right after the day value is edited

1.1 [27/04/2014]

• tidying and restructuring of code
• changed options page to auto save
• added textfield number check
• added working 0 days mode (no history)