Provide ability to have history capped

[jeffbski]

Add the ability to have history capped to a certain number of operations which is good for long running systems or heavy data use.

By specifying the optional limit, the history mechanism will release old records once it hits the threshold.

The limit is optional and if omitted, then the limit is Infinity.

// optionalKey and/or optionalLimit can be omitted from the call
var optionalLimit = 10; // only keep last 10 of history, default Infinity
var structure = immstruct.withHistory('optionalKey', optionalLimit, { 'foo': 'bar' });
var structureNoKey = immstruct.withHistory(optionalLimit, { 'foo': 'bar' });

var structureNoKeyUnlimited = immstruct.withHistory({ 'foo': 'bar' });
var structureKeyUnlimited = immstruct.withHistory('foo', { 'foo': 'bar' });

[mikaelbr]

Looks good to me. Makes sense to have a limit, for long living apps. Maybe you could squash the commits and I'll merge it?

[jeffbski]

ok, will do.

[jeffbski]

I'm going to make one more change to the commit comment and it will be ready.

[jeffbski]

ok @mikaelbr I believe it is ready to merge.

[mikaelbr]

Very good. Merging now. :cake:

[jeffbski]

Excellent. Thanks.