Temporary fix for consecuent ko.mapping.fromJS calls

[lisandropuzzolo]

If you make consecuent calls to ko.mapping.fromJS(), in some cases the computables involved on the viewmodels are not evaluated correctly.
This behaviour is noticeable if you use Validation plugin.

I made this fix, so you can call ko.mapping.evaluateDependentObservables() between each ko.mapping.fromJS(...) call.

ko.mapping.fromJS(....); // mapping the first viewmodel
ko.mapping.evaluateDependentObservables();
ko.mapping.fromJS(....); // mapping the second viewmodel

// now both viewmodels are working correctly, specially those using validation plugin.

[lisandropuzzolo]

I updated the fiddle that shows the problem, and now it run two tests:

1. One mapping.fromJS(...) call
2. Two consecutive mapping.fromJS(...) calls.
   http://jsfiddle.net/VCP4t/2/

As you can see, on the first test, after a setTimeout the .isValid() returns what is expected (false),
but on the second test, ir returns true, when the expected value is false.

[drdamour]

if you can make this call and evaluate the dependent observables during the current execution thread (IE: not in a function run from setTimeout or setImmediate) then why not just do it always? If the setTimeout isn't required...why have it at all? I also commented on this over @ #95

[drdamour]

i put together an alternative method of fixing this with included updated unit tests @ #126

[sagacity]

This is fixed in 0cfd93c thanks to drdamour's pull request