Images in srcset should be included too

[marijnvdwerf]

Expected:
Image with both src and srcset has both images included

<img src="/images/logo.png" srcset="/images/logo@2x.png 2x" />

Actual:
Image only has src included as data URI. srcset is left unchanged

[tommedema]

@jrit in addition to the above, favicons and fonts are also not embedded; do you plan to do this or welcome a PR for this? should there be config to enable/disable types of assets?

[jrit]

@tommedema I'd welcome a PR, but don't plan to add that myself. My preference would be a config similar to how the existing configs work per asset type, and with a similar rationale for defaults.

[tommedema]

@jrit if I ever get to this in the future, do you think that the current logic should be refactored to have a single detection and replacement engine in which differences for each type can be injected?

Currently the code is not very DRY, which is already apparent from a glance at the code:

This could be rewritten to 1 block of logic and 4 configuration entries. Wdyt?