Allow for arguments in HDate.prev()

[mennyg]

HDate.prev() currently only allows to go back one day. It would be great if we can be allowed to add arguments. Fro example, Hebcal.HDate.prev(7) would give me last week, and .prev(30) would give me a month ago.

[Scimonster]

Good idea! Would you be interesting in making a pull request with this?

[mennyg]

Would love to, but I'm quite new to extended functions and prototypes. Here is what I'm thinking, but it's not working on my side (hdate.js):

prototype.next = function (days) {
    return abs2hebrew(this.abs() + days).setLocation(this.lat, this.long);
};

prototype.prev = function (days) {
    return abs2hebrew(this.abs() - days).setLocation(this.lat, this.long);
};