preparing new axes positioning: getAxesPosition()

including helper functions:
- getNaturalFigureDimension
- getFigureDimensions
- getRelativeAxesPosition
Absolute positioning instead of aligning.
Bugfix: getRelativeAxesPosition() with multiple handles
Use the bounding box around the axes to rescale the plot.
Remove unused methods from the original alignment method.
Introduce the helpfer function convertUnits()
use convertUnits() to deal with different units.
convertUnits: implemented `pt` and some clean-up
Use `m2t.currentHandles.gcf` instead of `gcf`
Remove unused functions for axis/pgf corners
Merge 'Alternate positioning'
Output AlphaData to PNG dimensions

Dimensions need to match the figure dimensions.
When alpha = 1, it doesn't make sense pass along the data
Merge branch 'issue297' #297
Minimal versions increased

MATLAB R2014a and Octave 3.8 are  now the minimally supported versions
Add hint to switch off deprecation warning

This will help people who are stuck in a deprecated
environment such that they won't hate the deprecation check.
Merge branch 'versionBump'
[Fix #330, #322] scatter: single scatter non default size

Signed-off-by: Oleg Komarov <o.komarov11@imperial.ac.uk>
Merge branch 'fixScatterSize'
Fix #376: Output `m2t` from `getAxisOptions`

This is needed to handle custom color definitions in axis options.

Note that `m2t` is returned before `opts` such that it is inconvenient to
get the `opts` without `m2t`.
Merge branch 'issue376'