Modification to multiple functions and addition of various analyses.

1) Ellipse parameters are now expected to be SEMIMAJOR & SEMIMINOR axes. i.e. not diameters.
2) Convolve function modified to better deal with stack underflow in FFT routines
3) Removal of option to scale PSF to arbitrary height - unneccesary and can lead to problems. Normalisation of the PSF is now forced.
4) PSF FWHM determination has been improved in both user PSF-generation and PSF-read regimes. PSF stamps are now generated out to a user input confidence interval, instead of an arbitrary multiplier. Padding of Aperture stamps is also performed to this desired confidence level.
5) Users are now able to provide a single gain value in place of the name of an error map, for cases where the gain level is uniform but nonzero over an image.
6) Methods of dealing with apertures that lie accross the edge of a provided sourcemask has been adjusted. Where previously a simple multiplication of apertures with the mask occured (a 'blotting out' of part of the stamp), now an aperture is only accepted if it has a (user defined) fraction of the stamp within the transparent part of the mask.
7) Modification to the Sky Estimation routine. Routine now calculates the Sky RMS, Pearsons Normality Test p-value, Local Sky Flux, and 5sigma Detection Threshold for each provided aperture.
8) All added parameters have been similarly added to the output file write routine, and to the parameter file creation and read routines.