add execute_code

[hainm]

Aim:

• Quickly test new idea without recompile js code
• JS user can play around with NGL in python.

code = """
var stage = this.stage;
var view = this.stage.viewer;
for (x in view){
    console.log(x)
}
"""

v._remote_call('execute_code', target='Widget', args=[code])

or using shortcut
v._execute_js_code(code)

[hainm]

Some example:

Ligand viewer:

execute_code_ligand-viewer.txt (rename .txt to .ipynb)

[hainm]

We can copy and paste any code from here: http://nglviewer.org/ngl/gallery/index.html
to quickly create view in the notebook. Make sure to replace

var stage = new NGL.Stage( "viewport" );

by

var stage = this.stage; // Using existing stage from Widget.