core: fix for postback controller
core: refactor zotonic_compile. It could skip work
core: refacored zotonic_compile a little bit more.
core: set lager metadata for modules and per-site servers.
Issue #781
mod_signal: fix lager metadata init
Issue #781
mod_video_embed: correctly fetch preview images for youtube videos with a '#' in the url.
core: don't crash on strange timezones.
core: add 'protocol' to the list of controller parameters that are excluded from url-generation by controller_file_id and controller_redirect.

(cherry picked from commit 47c762eacae17ad8ad7d689530e585419244b8bb)

Conflicts:
	modules/mod_base/controllers/controller_file_id.erl
core: if depiction lookup fails due to a timeout, just return 'undefined' instead of crashing.

(cherry picked from commit d7ff3b01f6e6448d75ae495478899e61adc01ce0)
core: also add session_id and set_session_id to the argument filter.

(cherry picked from commit f280ace204fb3a50411f5d79626a605ea1ad5744)
mod_oembed/video_embed: expose preview fetch functions.

(cherry picked from commit c3fb1e50c6e2aae663d8eab91aea8a355a29acf4)
mod_oembd: don't crash on errornous preview urls.

(cherry picked from commit 681038a829b1723ccfed2de0c83d7c25edce461f)
mod_oembed: don't cache big thumbnails in the depcache, just request them again if needed more than once.

(cherry picked from commit 8bf8bb7c8eb4ce993ab8703548e20571580d2fb2)
mod_oembed: fix typo.

(cherry picked from commit bb87a7a304acb2ce3221ab584ceb42c6d16d24ae)
mod_survey: Return the (possibly generated) submission id, after insert
mod_base: Fix service_available/2 in controller_static_pages

7cd067f8ae078276912a12e8c6fc52d1a9b1d579 introduced a wrong webmachine
reply
mod_video: fixes for handling binaries returned from the z_string and other function (used to be lists)

(cherry picked from commit a3c234f0f7f68ab17c4dc05a72ff4fb3c3c7212b)
core: minor fix in mime-lookup for files not recognized by 'identify'

(cherry picked from commit 911e756157c2c7553add78fbe92acb30b6d85774)
Remove redundant is_protected check on resource

#786
doc: update menu documentation to reflect actual output of the module