remove photon filter for our feed work.

appears to have to be implemented in strip-gallery, as if it's done before the_content filters it doesn't work. ok to remove in main class. since strip-gallery is run regardless, I think this may be OK.

to address issue #12
jetpack_photon_skip_image filter moved to main class

if the filter is inside the conditional to check if photon is active, it does not seem to work universally on every single image. no idea why. leaving it outside of a conditional seems to be ok
add duplicate photon remove

Photon is pushy enough that we have to remove it everywhere. Still add it back in after we are done.
add fallback for older PHP
added missing text domain strings
fixed languages folder location
added Spanish translation files
refactor non plugin images and captions

Instead of doing if/elseif/else, first we set the style, and then change it if needed.
Partly needed to properly handle images with no width set in content. Too many
variables to sort through to properly assign width for feed at this time.
clarify comments
Merge branch 'feature/photon-support' into develop
added/changed error message

Added error message if RSS settings are for excerpt instead of full text, since plugin won't work.
Simplify/Alternate conflict error message now only shows on Media Settings page.
added condition for early return to fix feed

If the user has Summary selected for their RSS settings, the plugin should not run,
since it works on the full content, not the excerpt.
added vertical limit to email image size

Not necessary, but disconcerting to see 0 for the image size in plugins/widgets which
show it. Set as double the width so it will presumably not be hit.
updated README
updated Spanish files
update version
Merge branch 'develop'