Move TMB pictos to another location

[oscarfonts]

The TMB icons are published via dropbox public folder from a personal account: https://github.com/TMB-Barcelona/tmb.js/blob/develop/src/helpers/tmb.icon.js#L5 Dropbox will discontinue public folders on March 15 2017.

We need to move these resources to a better location. And make a test to be sure they are accessible.

Alternatives:

• Publish in this same repo, on gh-pages.
• Embed in javascript as base64 encoded data uris: https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/Data_URIs

Better alternatives (long run):

• Use a web font with all the scalable icons, and provide a CSS which willprovide semantic classnames and assign them the official RGB color.