Missing features

[simonrw]

This tracks features that are missing from the library that should be included. This is not a complete list, but mostly features that I use, or have been requested.

• [x] control mutability of files
• [x] read a fits image by start and number of elements
• [x] read a fits image by square region
• [x] read a fits column
• [x] read a fits column range
• [x] write a fits image by start and number of elements
• [x] write a fits image by square region
• [x] write a fits column
• [x] write a fits column range
• [ ] read/write variable length columns
• [x] read/write string columns
• [ ] null values
• [x] add/remove columns to a table
• [x] ~~ascii tables - do we want to support this?!~~
  • for now, we don't support ascii tables
• [x] copy hdu (#44)
• [x] get image data type
• [x] resize fits image (#31)
• [x] support extended filename syntax (66bcd871c6425ec0a1d982b729c635091037906f)
• [x] provide (safe) access to the underlying fitsio_sys::fitsfile object (#32)
• [x] delete hdu (#45)
• [x] get hdu name (#45)
• [x] get number of hdus (#45)
• [x] hdu iterator (#46)
• [x] support images which are not 2D
• [ ] change image data type issue