SUBPLOTNUMBER: For the numbering of subplots in the top left corner.
[For more than one subplot]
Syntax: h = subplotnumber;
numbering in the default format
(a),(b),... returns handle-array h.

h = subplotnumber(format)
numbering in user defined format. Returns
handle-array h.
e. g. h = subplotnumber('(A)');
or h = subplotnumber('1');

subplotnumber
default numbering without output

subplotnumber(format)
user defined numbering without output

subplotnumber('delete')
removes all numbering created by this
function

subplotnumber(format, [xp, yp])
subplotnumber([xp, yp])
adjustment of the position of the numbering

[For single axes (no subplots)]
Syntax: h = subplotnumber(number)
numbering with the string
'number' (outputs Text-Handle h)
e. g. h = subplotnumber('(b)');
or h = subplotnumber('2');

subplotnumber(number)
numbering with the string
'number' (no output)

subplotnumber(number, [xp, yp])
manual adjustment of the position

subplotnumber('delete')
removes all subplotnumbers created with
this function

Input arguments:
- format: Format of the numbering (string)
Supported formats:
- (a) - DEFAULT
- a
- (A)
- A
- (1)
- 1
Cursive and bold numbering can be added by adding:
\it (cursive) or \b (bold) to the format string.
e. g. format = '\it(a)';
format = '\ba';

- number: (in case of single axes) numbering to add to axes (string),
e. g. '(b)'
Cursive and bold numbering can be added by adding:
\it (cursive) or \b (bold) to the format string.
e. g. number = '\it(a)';
number = '\ba';

optional inputs:
- xp: x position (normalized) of the placement of the
subplotnumber
- yp: y position (normalized) of the placement of the
subplotnumber
Input as [xp, yp], a 1x2-double!

Output arguments (optional):
- h: Handle array of the placed text objects.
Ech text object is given the tag: 'subplotnumber'.

Hint:
By typing:
h = findobj(gcf,'Tag','subplotnumber');
subplotnumbers can be extracted from a figure.

Author: Marc Jakobi - 22.01.2016