Zoom/Crop into selection via brush selection

[cornhundred]

Allow users to selection section of the heatmap to zoom into.

Do not actually crop into this section, but just zoom in. Need to be careful about tracking zoom with this function. Also, improve camera resetting, ideally reset camera after zooming/panning event is over.

I'm going to probably just make this work through cropping. I'll build a general method to remake the entire viz based on filtering for an arbitrary set of rows/columns (dendrogram will not be shown, rearrange buttons will either be deactivated or reflect on-the-fly calculations). This general filter network method will be built off this method (https://github.com/MaayanLab/clustergrammer/blob/master/src/network/filter_network_using_new_nodes.js) and will be generalized to support dendrogram cropping, crop to zoomed area, and zoom into selection.

• get arbitrary network row/col filtering working
• set up SVG brush crop similar to brush_crop_matrix
  • need to do the algebra to find selected rows/cols on brushing