refactor(ngRepeat): use &1 instead of %2 for even odd checking

[demike]

use

index&1==0

instead of

index%2==0

for even odd checking

[mary-poppins]

Thanks for the PR!

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[jbruni]

It is breaking the build.

Use parenthesis so it performs correctly and return boolean instead of integer: (index&1)==0

[petebacondarwin]

Optimizations like this need to be supported by some evidence.
Here is a jsperf case http://jsperf.com/odd-and-even/2 which seems to show that the &1 case is 99% faster, which is quite convincing.
There are some concerns over using bitwise operators since JavaScript numbers are always floating point. In this case we are guaranteed that the numbers are positive integers so I guess it is safe to optimise.
@IgorMinar or @mhevery - do you have a view?

[petebacondarwin]

@demike - can you make sure you sign the CLA.
By the way I would say that this is a "refactor" not a "chore", since chores are more about the build and package process.

[demike]

Just signed the CLA.

[lgalfaso]

this PR is no longer valid as this change was done with f2fab49