This commit performs two tasks:
1. it exports the internal browser object (in owl.browser), for ease of
testing
2. it makes sure that Owl does not crash inside iframes in incognito
mode, because window.localStorage raises an exception in that case
closes#791
This could be done by each application, but it does cost only a few
lines of code, and it helps standardizing the Owl ecosystem.
For example, some library (such as o_spreadsheet) needs to mock side
effects, and Odoo also needs to do that, so this prevents duplicated effort.
closes#686
Géry Debongnie