gridster extra methods

Some new methods we need at Ducksboard to implement TV mode.

Two new distributions of Gridster are generated with grunt:
    - jquery.gridster.with-extras.js
    - jquery.gridster.with-extras.min.js

src/jquery.gridster.extras.js

@@ -0,0 +1,165 @@
+;(function($, window, document, undefined) {
+
+    var fn = $.Gridster;
+
+    fn.widgets_in_col = function(col) {
+        if (!this.gridmap[col]) {
+            return false;
+        }
+
+        for (var i = this.gridmap[col].length - 1; i >= 0; i--) {
+            if (this.is_widget(col, i) !== false) {
+                return true;
+            }
+        }
+
+        return false;
+    };
+
+    fn.widgets_in_row = function(row) {
+        for (var i = this.gridmap.length; i >= 1; i--) {
+            if (this.is_widget(i, row) !== false) {
+                return true;
+            }
+        }
+
+        return false;
+    };
+
+
+    fn.widgets_in_range = function(col1, row1, col2, row2) {
+        var valid_cols = [];
+        var valid_rows = [];
+        var $widgets = $([]);
+        var c, r, $w, wgd;
+
+        for (c = col2; c >= col1; c--) {
+            for (r = row2; r >= row1; r--) {
+                $w = this.is_widget(c, r);
+
+                if ($w !== false) {
+                    wgd = $w.data('coords').grid;
+                    if (wgd.col >= col1 && wgd.col <= col2 &&
+                        wgd.row >= row1 && wgd.row <= row2
+                       ) {
+                        $widgets = $widgets.add($w);
+                    }
+                }
+            }
+        }
+
+        return $widgets;
+    };
+
+
+    fn.get_bottom_most_occupied_cell = function() {
+        var row = 0;
+        var col = 0;
+        this.for_each_cell(function($el, c, r) {
+            if ($el && r > row) {
+                row = r;
+                col = c;
+            }
+        });
+
+        return {col: col, row: row};
+    };
+
+
+    fn.get_right_most_occupied_cell = function() {
+        var row = 0;
+        var col = 0;
+        this.for_each_cell(function($el, c, r) {
+            if ($el) {
+                row = r;
+                col = c;
+                return false;
+            }
+        });
+
+        return {col: col, row: row};
+    };
+
+
+    fn.for_each_cell = function(callback, gridmap) {
+        gridmap || (gridmap = this.gridmap);
+        var cols = gridmap.length;
+        var rows = gridmap[1].length;
+
+        cols_iter:
+        for (var c = cols - 1; c >= 1; c--) {
+            for (var r = rows - 1; r >= 1; r--) {
+                var $el = gridmap[c] && gridmap[c][r];
+                if (callback) {
+                    if (callback.call(this, $el, c, r) === false) {
+                        break cols_iter;
+                    } else { continue; }
+                }
+            }
+        }
+    };
+
+
+    fn.next_position_in_range = function(size_x, size_y, max_rows) {
+        size_x || (size_x = 1);
+        size_y || (size_y = 1);
+        var ga = this.gridmap;
+        var cols_l = ga.length;
+        var valid_pos = [];
+        var rows_l;
+
+        for (var c = 1; c < cols_l; c++) {
+            rows_l = max_rows || ga[c].length;
+            for (var r = 1; r <= rows_l; r++) {
+                var can_move_to = this.can_move_to({
+                    size_x: size_x,
+                    size_y: size_y
+                }, c, r, max_rows);
+
+                if (can_move_to) {
+                    valid_pos.push({
+                        col: c,
+                        row: r,
+                        size_y: size_y,
+                        size_x: size_x
+                    });
+                }
+            }
+        }
+
+        if (valid_pos.length >= 1) {
+            return this.sort_by_col_asc(valid_pos)[0];
+        }
+
+        return false;
+    };
+
+
+    fn.closest_to_right = function(col, row) {
+        if (!this.gridmap[col]) { return false; }
+        var cols_l = this.gridmap.length - 1;
+
+        for (var c = col; c <= cols_l; c++) {
+            if (this.gridmap[c][row]) {
+                return { col: c, row: row };
+            }
+        }
+
+        return false;
+    };
+
+
+    fn.closest_to_left = function(col, row) {
+        var cols_l = this.gridmap.length - 1;
+        if (!this.gridmap[col]) { return false; }
+
+        for (var c = col; c >= 1; c--) {
+            if (this.gridmap[c][row]) {
+                return { col: c, row: row };
+            }
+        }
+
+        return false;
+    };
+
+}(jQuery, window, document));