Added uJy2mag & mag2uJy.
Fixed potential bug in affinefit(), slight refactoring.
Added photinfo to gitignore.
Added length() function.
Added strn_sci() and strna_sci() functions.
Added align_left(), align_right() and align_center().
Improved photinfo to be more readable, and display depth of each band.
Fixed nested struct reading from FITS files.
Added shuffle().
Added shuffle() function.
Fixed photinfo not printing correct 3-sigma and 5-sigma counts, improved performances and changed depth from 1-sigma to 3-sigma.
Added 'min_id' and 'max_id' functions.
Refactored code in math.hpp.
Added convex_hull().
Added 'field_area' function.
'photinfo' now also prints the area covered by each band.