Much improved auto-detection of @chainable.

We're now able to determine if the execution can flow through a control
structure or will the control structure always result in a return statement.
Replace FunctionAst#chainable? with #return_types.

As a first step in expanding FunctionAst to do full detection of
various return types, not just whether we're returning this or
something else.
Detection of undefined return value.
Detection of boolean return values.
Detection of string return values.
Detection of regexp return values.
Fixed hard-coded offset on overview panel scroll into view.
Merge pull request #246 from garryyao/issue/245

Fixed hard-coded offset on overview panel scroll into view.
Log messages of extract.js script to stderr.

This way the stdout can be directed to file and the file will only
contain SQL that can be fed into MySQL.

Also added error message when connecting to mongodb fails.
Define the comments test database also in config file.
Eliminate recreation of database from testing.

Instead of dropping and recreating the database we now drop all the
tables and then recreate them.  This is because in our staging server I
currently have just one database available and I can't drop and recreate
it to run tests in it.

Additionally eliminated the update_votes.sql script - the triggers
themselves take care of votes being calculated.
Create nodejs script to load the test database.
Remove the examples.sql file.

This was to just try out some queries.
Most of them have now been implemented.
Force the use of express 3.0.0rc3.

The latest 3.0.0rc4 release broke JSONP requests handling.
Additionally I'm getting some strange 404 errors.
Fix comment author in comment notification e-mail.

Previously the receiver of comment was used in place of the actual
author.
Avoid creating excessive amounts of sessions.

Store the session cookie also when user is not logged in - just to keep
his session ID and not create a new session for each and every request.

Additionally use Ext.JSON instead of JSON.
New recent comments page.

The page is now also visible to normal users, with the only difference
that hideRead checkbox is only shown for moderators.

The page is divided into two sections: comments & users.

The comments section has two tabs which determine how the comments are
sorted (instead of a checkbox determining it).

The users section has a list of all users sorted by votes.
Add list of users sorted by comment counts.

Now the tab panel of users list makes sense.
Change rendering of links in recent comments list.

Let links be blue as they should be.
Hide the member type info from link - it's not that important.
Fix jasmine tests for Comments.getTopUsers.