Changing error.php?mode=js from text/plain to text/javascript 

Changing the js mimetype to text/javascript to avoid problems with some proxy configurations.
Merge pull request #216 from PerryWerneck/master

Changing mimetype reported by errors.php?mode=js to avoi proxy problems.
properly handle per-feed hide_images setting in three panel mode (closes #706)
fix nsfw plugin
hide warning when checking for tt-rss tables if tables are not present
nsfw: fix wrong delimiter when expanding tag_cache
support custom order in generated feeds (closes #709)
opml: fix filter parameters inverse and title not being properly imported from OPML
add experimental floating title when scrolling long articles in combined mode
limit floatingTitle width
use text-overflow in floatingTitle
clamp content preview to single line in three panel mode
move notify a bit to the left so it woulnd't obscure browser scrollbar
unify excerpt font sizes for CDM and 3 panel mode, use single line headers in expandable mode
unify some cdm padding values with 3panel mode
block automarking headlines on scroll in unexpanded cdm because it doesn't work so well
remove single-line excerpts in widescreen 3panel mode because it breaks layout
Fix automatic language detection for registered users

If you do not choose a language, the db pref record for your language is an empty string, but if you choose "automatic detection" and save your prefs, it's "auto".
"auto" in startup_gettext function prevents ttrss to choose the appropriate language.
Merge pull request #217 from ldidry/master

Fix automatic language detection for registered users
experimentally disable unnecessary folder icons for feedTree