Changed std::pair to QPair in Image Source class

Intended to keep consistency with other Qt containers.
Updated README

Removed references to 7zip and added a short list of application
features.
Set cursor to blank when panning images

When clicking and dragging an image in the ImageView class, the cursor
is set to blank (invisible) until the mouse is released.
Added SharedTemporaryDirectory class

The SharedTemporaryDirectory class represents a temporary directory that
can be shared amongst objects and processes.
Commented SharedTemporaryDirectory class
Updated ImageSource comments

Added more detailed description to each class that inherits from
ImageSource.
Added path function to SharedTemporaryDirectory class

Returns the path to the temporary directory.
Intergrated SharedTemporaryDirectory into the QuaZipImageSource class
Bug fix: Fixed infinite loop caused by attempting to extract a file that already exists
Added fastHalfScale() function to the Utility namespace

Scales a copy of the given image to half its size and returns it. This
function has similar results to using smooth scaling, but is much
faster.
Added the roughlyEquals() function to the utility namespace

Returns whether or not the given arguments are roughly equal. Returns
true if the difference between the given arguments is less than the
given error; otherwise, false.
Added ImageViewer header file

The ImageViewer class represents a widget that can display an image. The
image can be manipulated through zooming. This class is intended to
replace the ImageView class.
Created the Imaging namespace

Moved Utility::fastHalfScale() to Imaging::halfScale().
Changed QuaZipImageSource::_extractWatcher from pointer to reference
Updated Imaging::halfScale to support being cancelled if running in a separate thread.

Renamed to halfScaled and added a QFutureWatcher<void>* argument. Also,
added comments and did minor refactoring.
Added the Imaging::bilinearScale() function

Scales a copy of the given image using bilinear resampling and returns
that copy. This function should generally only be used when scaling less
than 50%. Anything beyond this bound will have similar quality to
nearest neighbor.
Added alpha channel support to bilinear scaling.
Added the Imaging::evenDimensioned function

Crops a copy of the given image so that each dimension is evenly sized
(i.e. not an odd number length) and returns that copy.
Added the ImageViewer class.

Intended to replace the Imageview class, which is now removed. The
ImageViewer class represents a widget that can load and display an image
from a file. The image can be manipulated through zooming.