Limit infinite requests

[lmoureaux]

This adds two hard limits to database accesses:

• Never more than 1000 objects
• Never more than 10MB (reasoning: 10x more after parsing, makes for a large request but still fits)

We let JSON fail to parse incomplete objects when they are too large because httplib doesn't gives us a handle on the total (available) size.

Hopefully 1000 objects and 10MB this is large enough to allow normal usage while protecting ourselves.

[lmoureaux]

Thanks for the review! I updated the server-side code. I'm not sure if the webapp is prepared to handle errors and won't touch it (don't know much Angular, less so in 2010 style).