Use local copy of jQuery UI instead of CDN version

The Google CDN version has a lot of components that aren't needed. This way,
a smaller stylesheet and JS file have to be downloaded.
Fix window resize bug in fullscreen+grid modes

Now calls adjustRows instead of adjustPages if in grid mode. Still needs to
handle horizontal resizing though (issue #77).
Center pages in fullscreen mode - for #77
Reflow pages upon fullscreen grid resize

Closes #77. Some of the code in loadGrid() is moved out into the helper
function loadGridImages() so that it can be called after resizing. A new
function called resetPanelDims() has been created to take care of updating
settings.panelWidth/Height, taking into account the width of the scrollbar
(which fixes a minor bug that was present previously in fullscreen grid
view).

This reflowing may prove to be slow or annoying (in that it results in more
images downloaded than necessary). In that case, the function can be modified
to use a timer of ~100 ms or so (or more, or less) when deciding whether or
not to reflow. A second timer would be needed if this were to happen, and the
function would have to be called only when in grid view.
Check for g=true before entering fullscreen

Closes #78.
Change default font family and size
Increase default viewport margin from 200 to 400
Fix typo in settings (desiredYOfffset)
Use image tags and not bground images in grid

Required for JPEG2000 integration (issue #20) as IIPImage doesn't seem
able to serve .jp2 images at arbitrary heights/widths. Luckily, the images
served are pretty much always going to be larger than needed, so they'll
look fine (although it will result in larger file sizes than is absolutely
necessary).
Initialise verticalOffset to 1 in gotoPage

Regression fix for the poorly-thought-out change made in commit
c9db17ec4d7e11778211a350480e4cd0835ee9fb. Comments should be
trusted in the future.
Use * instead of *.tif in divaserve.php

Allows for .jp2 images. For issue #20.

This change assumes that only image files are contained in the given
directory, which seems to me a reasonable assumption to make.
Improve toolbar design

Summary of changes

* New icons for the "grid" and "link" buttons
* Gets rid of the external, Google-CDN-hosted jQuery UI js/css files and
  makes use of prepackaged ones (stripped of the unnecessary components
  and with some minor stylistic modifications) instead
* Better handling of sliders and switching between grid/document view
* Gets rid of pnotify as that is no longer needed for the fullscreen
  statusbar (results in better handling of the fullscreen statusbar in
  general)
* Slightly prettier design for the toolbar, in both fullscreen and
  regular mode

This commit is incomplete - some CSS/JS file cleanup is necessary and will
happen shortly.

Closes #74.
Prevent #h and #w hash params in fullscreen mode

This is only a temp fix - the height and width of the viewer should optimally
be stored before entering fullscreen.
Delete reference to pnotify.css
Check for toolbar before calling switchSlider

Fixes the toolbar when #g=true.
Change default permissions on temp directory
Toggle grid view icon (closes #81)

The icon itself doesn't look too great. Will improve later.
Remove width adjustment upon resize in fullscreen

If the width of the inner element is larger than the width of the window,
then it'll just be cut off horizontally. Recentering isn't as important.
Switch slider upon double-clicking in grid view

Bug fix.
Use LESS for stylesheets

Switched to pre-compiled LESS stylesheets. A non-minified version is saved
in css/diva.css, and a minified version is saved in css/diva.min.css.

This is a fairly large commit that involves the following changes:

* Cleaned up the stylesheets - smaller CSS file (diva.min.css is less than
  half the size of the two files, diva.css and jquery-ui.css, that it has
  replaced), less repetition and redundancy, cleaner and easier to follow.
* Removed css/jquery-ui.css
* Updated js/jquery-ui.js to change class names (in accordance with the
  class names in css/slider.less). This was done using a simple find and
  replace, since doing more than that using a minified file is difficult.
  Making the changes in the unminified file and then later compressing it
  is probably a good idea.
* Removed the images associated with the the jQuery UI styling.
* Added a fabfile to make LESS compilation and Javascript file minification
  easier.

Things to do:

* Finish styling for the slider (currently using temp colours)
* Move all colours into variables.less
* Add wiki documentation on using fabric and less