Split filterparserthread into .h and .cpp
Move libtorrent includes to .cpp

This commit probably fixes #2119.

The only important change in this commit is moving
session::get_ip_filter() from FilterParserThread::processFilterFile() to
FilterParserThread::run(). Previously we called it in main thread, but
now we calls it in worker thread. I don't now what libtorrent contract
about threads, but I assume that if it is ok to set_ip_filter from
other thread, it is ok to get it.
Split statusbar into .h and .cpp
Split trackerlogin into .h and .cpp
Merge pull request #2120 from sorokin/ip-filter-moc

split filterparserthread into .h and .cpp and (probably) fixes #2119
Remove extra double quotes
Add alt attribute to images
Add type attribute to style tag
Focus username input on load
Remove "Downloaded" from transferlist header and reduce column width
Change background color of filterlist on hover
Change background color of rows of torrent content
Don't show white parts when hovering over the elements of the menu
Alternate background color for torrent content

CSS3 support required.
Center vertically "+" image in tracker list
Change color of table header in bottom panel and add some padding
Minimize width of first column in transfer list
Fix disappearing transferlist list when zooming in the browser

When the page is zoomed in the browser, the transferlist doesn't fit
in the page and is moved below the left column, disappearing completely.

Allow elements to overlap the handle to prevent this from happening.

The error message is moved in the status bar since it's wrongly placed
because of the overlap.

Closes #603.
Use fake tristate checkbox on IE < 9 only
Reduce font size of priority combo boxes

They were too big in some cases (e.g. Firefox on Linux).