0.2

Re-write of the function to make use of grid graphics. 
Grid graphics allows users to modify the heatmap and extend the function in
ways that are not possible with traditional R graphics. For examples of how
to modify the plot using tools from the grid package, see the examples in 
the LDheatmap help file.

Changes to function arguments:
1. The function now allows gdat to be one of the following: 
- a data frame of genotypes
- an object of class LDheatmap
- a matrix of pairwise LD measurements.
The purpose of allowing gdat to be an object of class LDheatmap is to 
enable recycling of the LD measures calculations, that can be time consuming for large data files, from previous calls.
If gdat is of class LDheatmap, the function recycles pairwise LD 
measurements from the original call and ignores the argument LDmeasure specified by the user in the second call.

2. Arguments x.image.show, y.image.show no longer used.
to control the size of the image, use the viewport command from the grid package.
See the LDheatmap help file for examples.

3. Changes to argument names: LDmeas is now LDmeasure, line.position is now
geneMapLocation, x.length.position is now geneMapLabelX and
y.length.position is now geneMapLabelY.

4. New argument newpage controls whether the heatmap is to be drawn on a
new page. Default is to draw on a new page.

5. New argument name specifies the name of the top-level grid graphical object (grob) created by a call to the function LDheatmap. 
See the examples for usage in the LDheatmap help file.

Changes to function output:
A list of class 'LDheatmap' is produced. The list consists of the following items:
LDmatrix - A matrix of linkage disequilibrium measurements.
LDheatmapGrob - A graphical object. This object is first drawn and than 
returned by the LDheatmap function.
heatmapVP - The Viewport in which the LDheatmap plot is drawn.
genetic.distances - Vector of physical or genetic map distances.

The LDheatmap plot output has been converted to grid graphics and is
comprised of the following editable grid objects (grobs):
"heatMap" - the color image of the heat map with its main title 
"geneMap" - the genetic map drawn on a diagonal line against the heatmap
"Key" - the color key legend
For further information on how to customise these objects, see
the package demo and the examples in the LDheatmap help file.

New functions:
1. LDheatmap.highlight - Highlight a genetic region in the LD heatmap.
2. LDheatmap.marks - Plot a symbol in the centers of cells 
representing the pairwise linkage disequilibria of specified pairs 
of SNPs.


0.1-5

 * Changed title in DESCRIPTION file

0.1-3

 * Enable user to select his own color scheme or blueToRed color scheme

0.1-2

 * Fixed bug in number calculated for legend "Genetic Map Length:"

0.1-1

 * Changed DESCRIPTION file
