Add and and or helpers

[sanjeevkpandit]

• Add and and or helper.
• For and: this will accept two or more parameters and return true if all of them are true.
• For or: this will accept two or more parameters and return true if any of them is true.
• This will allow us to do:

{{#if (and value1 value2) }}
    // do Something
{{else}}
    // do something else
{{/if}}

{{#if (or value1 value2) }}
    // do Something
{{else}}
    // do something else
{{/if}}