Database improperly closed in example code

os.unlink(flaskr.DATABASE) causes the actual application database to be
purged; whereas, I reckon, one wants the _test_ database to be removed.
So every time I ran it, the test passed, but ended up crashing the live
app for want of a valid database.

I avoided using the sample code in examples/flaskr thus far, as I chose
to type out code from the turorial docs. The actual example code looks
good - at least to my beginner's eye.
fixes #677 - mistype in docs/quickstart
Add closing html tag
Move docs explaining instantiating Flask
Put the link to Flask class docs at the end.
Remove comma.
Flash messages signals

If we send a signal when a template is rendered why not when a message
is flashed? One real world use case is in tests, this signal should make
flash messages expectation easier to implement.
Update css.rst

Improved consistency: lower cased all hexadecimal descriptions of colors.
Merge pull request #689 from OrangeTux/patch-2

Update css.rst
Merge pull request #683 from alexcouper/master

Tiny changes to docs
Merge pull request #681 from dmizelle/docs-quickstart

fixes #677 - mistype in docs/quickstart
fix typo in quickstart guide
Added more information about app factories.
Merge pull request #693 from untitaker/factory_docs

Added more information about app factories.
Merge pull request #692 from mikegagnon/patch-1

fix typo in quickstart guide
Merge pull request #687 from poiati/flash-signal

Flash messages signals
Documented new signal message_flashed
Add import to jsonify example.
Fixed a few typos on quickstart
Updated jquery.rst with the current Google Developer hosted libraries URL and jquery version