Fixes Issue #941 Any theme in chain can contain targets file, and
site root can contain sass\less directory with uncompiled files
and targets file
Merge branch 'master' of https://github.com/getnikola/nikola

Conflicts:
	CHANGES.txt
Merge branch 'master' of https://github.com/getnikola/nikola
Merge remote-tracking branch 'upstream/master'

Conflicts:
	CHANGES.txt
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of github.com:ermeaney/nikola
Fix drafts being leaked in feeds.

This commit is a simple fix to work around the way `doit` seems to
handle file dependencies - if a file was a dependency for a task prior
to this run, but is no longer a dependency, the task is not run,
again. Only, the file dependencies in this run are checked for
changes.

We simply check use_in_feeds status for all the posts, to discover any
changes and regenerate the feed.

Fixes #934
Merge remote-tracking branch 'upstream/master'
add alias exts in COMPILERS for "translated" content without a def. lang post

when somebody had the old TRANSLATIONS_PATTERN="{path}.{ext}.{lang}"
DEFAULT_LANG="en"
and a post "something.rst.es" and no "something.rst", the former
would be considered a file with wrong extension
this commit adds aliases like ".rst.es" to the COMPILERS at runtime
move extension lang-alias creation code to Nikola.__init__

to create the aliases only once and not in each function call
flake8 style fixes
more flake8 style fixes
fix COMPILERS exts alias creation

splitext assumed the ext was a apth, not ext, so a small path
"f" had to be added first
fix recongnition of files with a longer ext

splitext would only get the shortest ext, so endswith() has to be used
add a test case for posts only in secondary languages.

this test however only checks that nikola runs and creates something
it cannot check that titles are translated (as we remove the
translation)
flake8 fixes

remove whitespace and do not redefine ext in list comp
fix error message
Fix #1022
report all collapsing tag errors, not just the 1st one
quit when there are any tag conflicts